One of the most common issues I have dealt with in pastoral counseling, especially during my years on the mission field where many were coming to faith, is believers who struggle with doubts concerning their salvation. We know that salvation is God’s gift to us by faith alone. The Scripture tells us, “Believe on the Lord Jesus, and you will be saved” (Acts 16:31). But once we have believed in the Lord Jesus, another question inevitably follows: “And how do I know I have believed?” It is this question that gnaws at the consciences of many.
To add to this dilemma, we know it is possible to think we have believed when this isn’t the case. There is, after all, such a thing as true and false faith, not to mention true and false assurance. A person can be deceived by a false profession of faith which produces a false sense of assurance when he or she has never exercised saving faith in the biblical sense of the term. Our Lord warned about this (Matt. 7:21–23). He said, “Strive to enter through the narrow gate, for many, I say to you, will seek to enter and will not be able” (Luke 13:23). The apostle John spoke of many in Christ’s presence who exercised counterfeit faith that was not efficacious to save (John 2:23–25; 8:30–44). Scripture is replete with warnings about religious deception and false professions of faith and even exhorts those who profess Christ to examine themselves to see if they are in the faith (2 Cor. 13:5). The sheer weight of these biblical texts causes many to fear as they struggle to attain to a sense of certainty with regard to their spiritual condition and eternal destiny.
But even though it is possible for the unregenerate to possess a false sense of assurance, it is also possible for the truly regenerate to struggle with assurance. The Puritans explained this by saying that the assurance is not necessarily “of the essence of faith” , distinguishing between saving faith and the assurance of saving faith. Faith and assurance of it are not synonymous. Salvation and the joy of salvation, although related, are not intrinsically united in the experience of the saint. The true believer may have many long, intense, and even hellish battles before attaining to a conscious, full, and well-grounded assurance of salvation. Or they might never enjoy a robust sense of assurance.
For this reason, Scripture exhorts us to be diligent in pursuing assurance. “Therefore, brethren, be even more diligent to make your call and election sure, for if you do these things you will never stumble” (2 Pet. 1:10). In this text, Peter is addressing “brethren” “who have obtained like precious faith with us by the righteousness of our God and Savior Jesus Christ” (1:1) but who nonetheless were in danger of lacking the assurance that they were cleansed from their former sins (1:9) due to a lack of diligence in pursuing the means of grace in order to progress in sanctification (1:5–8). We must never be slothful in seeking to enjoy full and unhindered fellowship with God through Bible study, prayer, worship, fellowship with the church, and all the other means that God has graciously provided for us to grow in our knowledge of Him and in spiritual fruitfulness. Assurance is a precious flower in the garden of God that must be handled with tender care and cultivated with a circumspect endeavoring after humble obedience to all the commandments of God.
How Do I Know I Have Believed?
Considering these things also helps us to answer our initial question: How do I know I’ve believed?
In the first place, we can be sure that we haven’t believed with a true, saving faith if our lives are characterized by continual, voluntary, and persistent disobedience to Christ. According to our Lord’s words in the Sermon on the Mount, those who cried out, “Lord, Lord” in the day of judgment didn’t truly possess a saving relationship with Him because they were “workers of lawlessness” (Matt. 7:23). The Greek word for lawlessness, “anomia”, literally means, “no-law” or “anti-law”. It refers to those who reject God’s law in rebellion by failing to obey it. In this case, such lawless living is indicative of a lack of saving faith. “He who says, ‘I know Him,’ and does not keep His commandments, is a liar, and the truth is not in him” (1 John 2:4). True faith manifests itself through practical obedience to God (James 2:14–26). It is “faith working through love” (Gal. 5:6) and “the obedience of faith” (Rom. 1:5) that supplies the necessary evidence of truly knowing Christ. This doesn’t mean that the true believer will yield impeccable obedience to God but that the general pattern of his life will be characterized by a sincere desire to honor His King and please his heavenly Father out of love.
Second, we can be sure we have believed and been justified if our faith is an effectual and operative faith which propels us forward in sanctification and growth in grace. Luther coined the term “living faith” to describe the nature of saving faith, because it is a faith that works, grows, and matures as it rests on Christ alone as the foundation of its confidence. This is in contrast to a dead faith which rests content in an empty profession and is void of good works (properly so-called) that characterize the regenerate life. The Puritans would often say that sanctification is the evidence of justification. While justification is invisible, sanctification brings forth fruit and evidence (Rom. 6:21–22). And the faith that justifies at the moment of conversion when we receive salvation continues to sanctify throughout our lives as we work out that salvation in our practical experience.
In 2 Peter chapter 1, the apostle knows that in order for the believer to enjoy the confident assurance of being in a state of grace, it is necessary to diligently pursue spiritual growth through faith in Christ, obedience to His commandments, the study of the Word, and fervent prayer. The Scriptures offer no assurance of salvation to those who consistently and obstinately fail to render sincere obedience from the heart to the Lord Jesus Christ. We cannot attain to the full assurance of faith by being slothful in our duty and slack in our perseverance. Assurance is for those who are “fervent in spirit, serving the Lord” (Rom. 12:11) as they diligently seek to be filled with all joy and peace in believing so that by the power of the Holy Spirit they may abound in hope (Rom. 15:13).
The Sources of Assurance
To where should we be looking in the hope of obtaining assurance? It is due to confusion about this that many believers suffer unnecessary affliction of soul as they anguish over whether they truly abide in a state of grace. Understanding the sources of our assurance as believers helps us to pursue it effectively. What, then, are the sources of assurance according to Scripture?
The First Epistle of John contains abundant teaching on this topic. It is the only book of the Bible written with the expressly stated purpose of helping those who already believe experience a well-grounded assurance of salvation. “These things I have written to you who believe in the name of the Son of God, that you may know that you have eternal life” (1 John 5:13). In this verse, the apostle makes a distinction between faith and assurance, addressing those who already have faith that they may be assured that their faith is genuine.
That which is intended to provide us with the confident assurance of our salvation is that which is written; “I write these things,” says John. It is the inscripturated Word of God that details the sources of the believer’s assurance. We must go to Scripture, and not to our own wavering opinions or faltering feelings, as we seek assurance. In 1 John, the apostle provides us with three fundamental sources of assurance.
The Promises of the Gospel Rooted
in the Finished Work of the Cross
John begins his epistle by calling our attention to the veracity and certainty of the historic, objective truth of the gospel event as accomplished in the person and through the work of Jesus Christ.
“That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, concerning the Word of life— the life was manifested, and we have seen, and bear witness, and declare to you that eternal life which was with the Father and was manifested to us— that which we have seen and heard we declare to you, that you also may have fellowship with us; and truly our fellowship is with the Father and with His Son Jesus Christ. And these things we write to you that your joy may be full” (1 John 1:1–4).
With these words, John emphasizes that the gospel is true and reliable. As an eyewitness to the life, death and resurrection of Christ, the apostle declares that who Jesus Christ is and what He accomplished serves as the basis for and foundation of the salvific fellowship the believer enjoys with God, and thus serves as the first and foremost fountain of the joy of the assurance of his salvation. John proceeds to state the specific promise of guaranteed eternal life predicated upon faith in Jesus Christ according to the inscripturated message of the apostolic witness to the gospel (1 John 2:23–25). The apostle makes clear that above all, Christ and His redemptive work alone must be the principle source of our assurance, as we embrace and appropriate the salvific benefits of that work by faith in the promises of salvation which are infallibly recorded in the Word of God.
The Testimony of the Holy Spirit
“And by this we know that He abides in us, by the Spirit whom He has given us” (1 John 3:24b). “By this we know that we abide in Him, and He in us, because He has given us of His Spirit” (1 John 4:13). Whereas the first source of assurance is rooted in the objective truth of the gospel as recorded in Scripture, this second source springs forth from the subjective, internal work of the Holy Spirit’s abiding influence in the heart of the believer. As the Spirit of God effectually causes faith to arise in our hearts through His regenerating work and continues to breathe life into that faith through His vivifying influence, He bears witness to the truth of Scripture within our hearts so as to cause us to be consciously aware of our participation in the saving power of the gospel as the particular recipients of the salvation accomplished at Christ’s cross.
Louis Berkhof explains what the testimony of the Spirit is. Readers may pardon me for the extended quotation, but Berkhof explicates the matter superbly enough to justify this lengthy interpolation:
“This testimony of the Holy Spirit should not be conceived of as a communication, conveyed to the believer by a secret voice, and giving him the assurance that he is a child of God; nor as a specific operation of the Holy Spirit on the mind, by which he directs attention to a passage of Scripture containing that assurance. Neither should it be regarded as a testimony that is given once for all at the moment of conversion, to which the believer can confidently appeal ever after, no matter whether he be yielding the fruits of the Spirit, or be following the lusts of the flesh. The Spirit of God testifies continually by his indwelling in the hearts of those that fear the Lord, and by all those gracious operations in the renewal of man that are so manifestly divine. He opens the eye of faith to the beauty and glory of the promises of God, illumines the mind so that their spiritual import is understood, and fills the heart with a sense of their appropriateness for lost sinners. He discloses to the spiritual eye the gracious character of the Saviour, causes the sinner to flee to him for refuge and to seek shelter in the shadow of his wings, and leads the soul to a trustful repose, safe in the arms of Jesus. He speaks in all the movements of the new life: in the love of God that is shed abroad in our hearts, in the filial spirit, the spirit of love and reverence and obedience, in his intercessions in the inner man with groanings that cannot be uttered, in the manifold experiences of comfort in suffering, strength in weakness, victory in seasons of temptation, and perseverence under the trials of faith. These are all works of the Holy Spirit. In so far as they are in us and abound, they bear witness to the reality of our reconciliation with God, and in the very voice of the Spirit give us the assurance that our sins are forgiven and that we are children of God. These vital spiritual affections shine with their own light, and thus constitute the testimony of the Holy Spirit that carries conviction to the soul. The more the life of faith develops, the greater our progress in the way of sanctification, the clearer will the voice of the spirit ring out, dispelling all doubts and filling the heart with joy and peace.” 
It couldn’t hardly be said any better. It is the work of the Holy Spirit that molds the affections of our hearts to esteem and treasure Jesus Christ, to love Him and desire to be in His presence, so that we continually and increasing enjoy fellowship with Him and thus rejoice in the assurance of our salvation. It is the Spirit who produces the subjective realities of the fruit of internal heart-holiness which manifest themselves objectively in practical obedience to Christ.
The Evidences of Regeneration
The larger part of 1 John is concerned with detailing those identifying characteristics which mark the general pattern of living and habitual practice of the child of God. Those who are born of God walk in the light of the truth and holiness of God (1 John 1:5–7), they confess their sins regularly as they evince a sober sensitivity to sin (1 John 1:8–10), they observe the commandments of the Lord in humble submission to God’s will (1 John 2:3–6), they are not characterized by hatred but rather love for their fellow believers (1 John 2:7–11), they experience progressive and continual spiritual growth (1 John 2:12–14), they are not dominated by inordinate affection for the fallen, satanic world system (1 John 2:15–17), they are by grace preserved so that they persevere in the faith (1 John 2:18–19), they confess Christian orthodoxy especially with regard to the doctrine of Christ (1 John 2:20–27), they are characterized by a general pattern of persistent striving after practical righteousness (1 John 2:29–3:10), they seek to continually procure and enjoy a clean conscience in the presence of God (1 John 3:19–22), and they love the Lord their God sincerely even as they abide in His love (1 John 4:7).
These fruits of a regenerating work of the Spirit in the life of the Christian constitute the evidence of what is always the case when one has been truly born of God. According to the apostle, every real Christian will be characterized by these things—at least to some considerable degree—in his experience. Those who lack the fruits of regeneration lack eternal life and yet abide in a state of spiritual death.
As one compares his lifestyle to that which is set forth of the genuine believer in the Word of God, if the general pattern of his conduct concords with the descriptive realities of genuine Christianity outlined in Scripture, he can be confident that God indeed is at work in him “to will and to do for His good pleasure” (Phil. 2:12–13). This in turn provides something of an objective way to discern if one truly abides in a state of grace. Those whose lives are marked by the fruit of regeneration can be confident that they have eternal life, and thus be assured by the testimony of God’s Word that their salvation is genuine; those whose lives are marked by an absence of the fruit of regeneration can be confident they abide in spiritual death, and thus be assured by the testimony of God’s Word that they are bound for Hell in their present condition (in which case they must turn and be converted that their sins may be blotted out).
This is what Reformed theology refers to when it speaks of “the reflex act of faith.” Knowing that saving faith is a living faith that produces spiritual fruits and manifests its vitality in practical ways, we can reflect on the fruits that are evident in our lives, and if those fruits are consonant with what Scripture describes relative to the fruits of genuine faith, we can safely conclude that God the Holy Spirit has made us partakers of the transforming power of the gospel by His grace.
Maintaining Biblical Balance
It is imperative that we maintain these three sources of assurance in biblical balance. The order in which I have laid them out here is not done carelessly. While the importance of all three sources of assurance should never be diminished, and we should never so emphasize one to the detriment of appreciating the others, we should also prioritize them in the order set forth here so as to give due precedence to that which is first in order of importance. I have listed these sources of assurance not only in a logical order, but also in theological order. Assurance is based on God’s Word, produced by the Holy Spirit, and confirmed by the life of faith and piety. This is vital to understand, and many believers, by failing to grasp these simple truths, thrust themselves into unnecessary troubles.
Many believers who have struggled to have assurance have struggled the way they have because of an imbalanced assessment of their standing in grace owing to their prioritization of the third source of assurance over the first source of assurance. That is, by falling into an obsessive practice of introspection they turn the eyes of their hope inwardly to scrutinize themselves. They grope about for some certain evidence of regeneration in the midst of a far-from-perfect obedience rather than lifting their eyes upward to behold the perfect righteousness of their Mediator and Advocate. They fall into the subtle snare of seeking assurance primarily by looking to their own performance and works rather than resting in simple, childlike faith in the finished work of the cross. In doing so, they struggle frequently as their minds are buffeted with many doubts since they are seeking perfect assurance from imperfect performance and flawed personal righteousness.
This subtle trap can become an abyss of endless self-examination. For we know that in order to be accepted in the presence of a just and holy God, nothing less than perfect righteousness is needful. But those who look to themselves to find a sufficient degree of righteousness or holiness to commend them to God can only despair of finding hope there because they can never attain to the perfection their sensitive conscience so ardently desires. As they examine themselves for the evidences of regeneration, they consider their actions, thoughts and motives; they question themselves incessantly out of the desire to be sure that the fruit of true piety has de facto been worked in their hearts and lives. But the problem with over-analyzing our own piety and motives is that it is like peeling off the layers of an onion—after advancing through one layer there is yet another, and then another, and another. Indeed, incessant introspection has at least one thing in common with peeling onions—they both make you cry. Who can understand the depths of his own heart? Who can perfectly discern his own motives? “Who can say, ‘I have made my heart pure; I am clean from my sin’?” (Prov. 20:9).
Never will we find within ourselves the source of confidence we need to experience the full assurance of faith. Our primary source of assurance must be the infallible Word and finished work of our Lord and Savior. This is why it is so important to understand the fruits of regeneration and how they bear witness to faith within—never apart from—the gracious context of the saving work of Christ and the promises of the covenant of grace. After all, we have nothing to boast of in ourselves. As the Puritans were apt to say, apart from being sanctified unto God by the blood of Jesus, the best of our good deeds would merit nothing short of eternal damnation. A well-informed faith is self-deprecating with respect to personal performance and Christ-magnifying with a view to God’s performance. It leads one to say with Paul, “But God forbid that I should boast except in the cross of our Lord Jesus Christ, by whom the world has been crucified to me, and I to the world” (Gal. 6:14).
Believer, do you struggle with assurance? Do you face anxiety over whether you are saved or not? Lift up your eyes and “behold the Lamb of God who takes away the sin of the world” (John 1:29).
Whether you are truly regenerate or not, I tell you, the remedy involves a look to the same Sin-bearer as your source of righteousness and peace before God. Look away from self to Christ, placing all your trust and hope and confidence in Him. If you are saved but struggling with assurance, only Christ can speak peace to your troubled soul and calm the turbulent waters of doubts and fears. If you are not saved, in Christ alone is the righteousness by which you can be justified in the presence of God. So, whether you are saved or lost, run to the open arms of the Son of God, “looking unto Jesus, the author and finisher of our faith” (Heb. 12:2). Embrace the objective promise of the Word and receive the whole Christ, just as He is set forth in the Scriptures. Make your prayer to resonate with that of the psalmist when he exclaimed, “Be my strong refuge, to which I may resort continually; You have given the commandment to save me, for You are my rock and my fortress” (Ps. 71:3). Pray and pray and continue to pray in earnest as you pursue the means of grace until you are sure that God has implanted a Spirit-wrought faith in your heart and sealed to you all the precious promises of His Word. And may your daily walk be characterized by ongoing and ever-deepening expressions of faith and repentance as you turn from self to Christ more fully every day.
 The Westminster Confession of Faith, 18.3.
 Louis Berkhof, The Assurance of Faith (Grand Rapids, MI: WM. B. Eerdmans Publishing Co., 1939), 62.