17 Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. 18 For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. 19 Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven.
What: Christ teaches that he does not relax but upholds the righteousness of the Law.
How: By denying he has intention to undo it, by asserting his purpose to uphold it, by teaching its perpetual duration, by affirming the exhaustive scope of its immutably inscripturated testimony, and by insisting on its binding moral authority as an issue that is determinative for one’s eternal salvation and for eternal rewards.
Why: Under the leadership of the scribes and Pharisees, Second Temple Judaism at large had lapsed into a hypocritical externalism that inordinately prioritized the observance of Jewish tradition while failing to stress a more important internal righteousness of heart (see Matt. 23:25). At the same time, these religious leaders would falsely accuse Jesus of undermining the Law (Matt. 15:1–2). Jesus teaches that they are the ones who relax the Law and that he is the One who gives it due honor.
Whereunto: Jesus vindicates himself and his teaching, exposes the hypocrisy of his opponents, and instructs his followers in what true righteousness looks like. He effectively establishes a foundation for new covenant ethics that honors all of God’s previous revelation.
This passage is the heart of the Sermon of the Mount. It serves as the introduction by which Jesus concisely summarizes what he is going to teach in the rest of the Sermon. “The Law” and “the Prophets” forms an inclusio, a phrase that introduces the body of the Sermon in verse 17 and is repeated to conclude this main body in chapter 7 and verse 12. As an introduction that summarizes Christ’s handling of the Law, our passage also provides a hermeneutical grid by which the reader is to interpret his exposition of the Law that follows. Any interpretation that would understand Jesus’s words as annulling, retracting, or relaxing the commandments he cites from the Old Testament would be incorrect since his emphatic insistence to the contrary is so clearly stated in this passage. Though his Jewish opponents accused him of antinomianism, Jesus, as the Messianic servant of Yahweh, came to “magnify the law, and make it honourable” (Isa. 42:10). Far from diminishing the force of the Law, Jesus expounds the spiritual nature of it. He eschews the externalism of pervading Pharisaic religion and magnifies the Law’s exigencies on the whole man, especially on the internal life of the mind, the affections, and the will (cf. Isa. 51:7). Ultimately, the standard for righteousness he derives from his authoritative interpretation of the Law far exceeds the superficial and hypocritical righteousness of the religious leaders of the Jewish nation.
Verse 17: The Purpose of Christ’s Mission Relative to the Law
In verse 17 Jesus says, “Think not that I am come to destroy the law, or the prophets.” The opening words are a prohibition, limiting what we should think about him, his mission, and his relationship to the Law and Old Testament Scriptures as a whole. “Think not” (Μὴ νομίσητε) is meant to contradict the prejudices, false assumptions, and erroneous conclusions that would presume that his purpose was in any way contrary to the Law. The Lord was aware of the misconceptions that were fomenting concerning him, and he intended to refute the objections that men would concoct in protest of his Messianic identity. Luther keenly observes, “Hence He explains from the outset that He has no intention of abolishing the Law, but had come for the very purpose of correcting and confirming the teaching of the Law in opposition to those who were weakening it by their teaching.” Any assumption that would interpret Jesus as being in opposition to any point of the Law is expressly disowned and is therefore not a viable interpretation of his teaching.
“The law or the prophets” refers to the entire canon of the Hebrew Scriptures (cf. Matt. 7:12; 22:40). A double infinitive of purpose is employed in order to summarize what his Messianic mission does not and does intend to bring about. Jesus did not come “to destroy” (καταλῦσαι), that is, to abolish, or “to end the effect or validity of” anything in these Scriptures. But (ἀλλὰ), by way of antithetical contrast, he did come “to fulfill” (πληρῶσαι) them.
A great deal of interpretive weight rests on the meaning of “fulfill” (πληρόω). Many options have been suggested, some of the majors ones include: (1) Jesus came to obey the commandments of the Law, perhaps vicariously as Mediator; (2) Jesus filled up what was lacking in the Law in order to perfect its deficiencies; (3) Jesus confirms the Law in his teaching and deeds; (4) Jesus is making a redemptive-historical statement of prophetic anticipation and fulfillment, signifying that he fulfills Messianic expectation.
It would seem that the first option (1), though theologically correct, is inadequate since the rest of the Sermon engages in experiential application of the Law to people, dealing with ethics, suggesting that it is not merely Jesus’s relationship to the Law that is in view. The second (2) would seem to interpret Jesus as having a negative view of the Law, would be redemptive-historically disjunctive contrary to the pervading emphasis of the text, and has been incorrectly taken up by Dispensationalists and others in support of the abolishment of the Decalogue. The third option has much to commend it, for it can be demonstrated from the following “antitheses” in Matthew 5:21-48, since in each one Jesus corrects traditional rabbinical contortions of the commandments he cites and explicates their true intent according to the fuller light he brings as the new “prophet like unto” Moses (Deut. 18:15). The fourth option (4) also seems plausible. As Carson demonstrates, it fits well with Matthew’s own use of πληρόω in the “fulfillment formulas” elsewhere in his Gospel. In each case, eschatological Messianic fulfillment is cited. These passages provide overwhelming evidence that Matthew customarily uses πληρόω in light of prophetic Messianic expectation, and disjoining its use in 5:17 from this surrounding contextual precedent would need substantial justification to rule it out. No such internal justification can be discerned as far as I can tell. Furthermore, the Law and the Prophets are in view—every jot and tittle of them—and not only the moral commandments of the Law. Plus, the following clause in verse 18 speaks of prophetic fulfillment. However, to limit our understanding of πληρόω in Matthew 5:17 to this fourth option exclusively does not fit with the context of verse 19, which stresses keeping the commandments. It does not fit with the rest of the Sermon either, which places much greater weight on the exposition and moral application of the Law than on prophetic fulfillment.
Therefore, it seems best to take the meaning of πληρόω in 5:17 as a combination of options three (3) and four (4). These are not logically contradictory but harmoniously coalesce. The rest of the New Testament provides ample support for both, and by the analogia fide and further theological reflection, this can be expanded to include all the ways in which Christ confirms the moral validity and fulfills the prophetic anticipation of the entire Old Testament.
Verse 18: The Law’s Perpetual Validity
“For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.” These words stress the perpetual validity of the entire Hebrew canon as infallible and authoritative Scripture. It was to the Jews that the oracles of God were committed (Rom. 3:2) and Jesus here sets his seal of approval on that canon. His coming does not render obsolete any detail of the Old Testament as God’s Word. All Scripture remains useful as the breathed-out self-revelation of God, his ways, and his will. It is still fully relevant and instructive for the Christian and in light of Christological fulfillment, interpreted Christologically, it is an able communicator of God’s preceptive will (2 Tim. 3:15–16).
The divine preservation of Scripture is also implied in verse 18. The validity of the Law and the Prophets encompasses all time, all human history, from the moment of their initial inscripturation through the first advent of Christ all the way to the end of the age. And this divine preservation also extends to every detail. Every word of God is more fixed and secure than the current created order (cf. Ps. 12:6–7; 119:89).
The stress on every iota (ἰῶτα, referring originally to the yod in the Hebrew oracles) and every tittle (smallest stroke of the pen) bears an ethical character in this context. It is all ethically authoritative. Keener observes, “Later rabbis told the story that when God changed Sarai’s name to Sarah, the yod that was removed complained to God for generations till he reinserted it, this time in Joshua’s name. Jewish teachers used illustrations like this to make the point that the Law was sacred and one could not regard any part as too small to be worth keeping.” Every detail matters, for it is there by divine design. The Hebrew canon in all its moral and preceptive force remains fully intact at least until the consummate eschaton when “heaven and earth pass.”
Verses 19-20: The Law’s Morally Binding Authority
“Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven.” To “break” the commandment translates λύω, which can vary in nuance from “destroy” to “loosen” or “relax.” Jewish rabbis would insist that whether a commandment is as “weighty” as the fifth commandment of the Decalogue or as “light” as preserving the life of a bird (Deut. 22:7), the Law must be observed. Christ echoes this high regard for all of God’s commandments. He differentiated between lighter and weightier matters of the Law (Matt. 23:23), but he never made the lighter matters a matter of indifference. No commandment, no matter how seemingly inconsequential, can be safely disregarded without repercussions of eternal import. The right attitude toward every moral obligation of the Law is to tremble before it out of reverence for the majesty of the Lawgiver, striving to honor it as an expression of love for him in circumspect and universal holiness.
“The kingdom of heaven” probably does not here refer to the visible church among whom the unregenerate are present but to abiding truly under the salvific sphere of God’s reign of grace. Since the Lord is speaking of those who will be “in the kingdom of heaven,” eternal rewards are in view in verse 19. Though breaking the least commandment may not anathematize the soul for eternity, it is nonetheless authoritative, and one will have to render an account to God for it. Such a person may scarcely make it into the Kingdom (cf. 1 Cor. 3:15).
The Lord goes on to declare who will and will not enter the Kingdom: “For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.” Due to the prior statement of doing and keeping the commandments personally, it would be contextually unfitting if this were referring to the necessity of receiving a righteousness forensically imputed. Jesus is calling for the fruit of practical obedience as the indispensable evidence of a life transformed by grace (cf. Matt. 7:15–27). This practical righteousness must shape the inner man with integrity, resulting in obedience from the heart, not merely external conformity to a law internally despised, as was the case with the scribes and Pharisees. Such righteousness constitutes the vindication of the faith that justifies (James 2:14–26); it is what will vindicate one’s profession before the judgment seat of Christ, ushering one into the kingdom in its eschatological and consummate glory (cf. Matt. 25:31–46).
Matthew 5:17–20 underscores the central importance of the Law and the Old Testament Scriptures for the follower of Jesus as the expected Messiah. His coming does not annul them but fulfills them. He fulfills the ceremonial, civil, and moral aspects of the Law and the way they come to us are now mediated through his person. But this mediation does not relax the moral law, nor does it diminish the imperatival force of any morally binding implication of Old Testament revelation. Though we are not under the old covenant, it is all applicable to us as we stand related to the Law and the Prophets in Christ, to whom they pointed, and whom they anticipated. The Law and the Prophets interpreted Christologically remain morally binding for the new covenant believer and they must be esteemed with utmost reverence, handled with utmost care, and obeyed with the most circumspect diligence. In summary, to quote the words of J.C. Ryle, Christ teaches us that we must “beware of despising the Old Testament under any pretense whatever,” and “beware of despising the Law of the Ten Commandments,” and “beware of supposing that the Gospel has lowered the standard of personal holiness.”
 Gr. κεραία. The smallest distinguishing mark of a written character. “Lit. ‘horn’, then anything that projects like a horn, projection, hook as part of a letter, a serif.” William Arndt, Frederick W. Danker, and Walter Bauer, A Greek-English Lexicon of the New Testament and Other Early Christian Literature (Chicago: University of Chicago Press, 2000), 540 (henceforth, I will abbreviate this resource as BDAG).
 It is perplexing why major translations do not literally render the adjectival modifier πολύς into English. The ‘surpassing’ of which the Lord speaks receives emphatic emphasis in the text due to the prioritized placement of περισσεύω and because of the adjective πολύς. My translation seeks to bring out some of the force of this emphasis. No doubt, the Lord intends his words to have a shock effect. The syntactical emphasis seeks to communicate that and I think it should be preserved in the English.
 See Vos’s anaylsis of Jesus’s critique of Jewish ethics in Geerhardus Vos, Biblical Theology: Old and New Testaments (Eugene, OR: Wipf & Stock Publishers, 2003), 395–396.
 Calvin observed, “[Jesus] boldly refutes the base reproaches and slanders, by which his enemies laboured to make his preaching infamous or suspected.” John Calvin and William Pringle, Commentary on a Harmony of the Evangelists Matthew, Mark, and Luke, vol. 1 (Bellingham, WA: Logos Bible Software, 2010), 276.
 D.A. Carson, Matthew, in Expositor’s Bible Commentary, vol. 8, ed. Frank E. Gaebelein (Grand Rapids: Zondervan, 1984), 142; James Montgomery Boice, The Gospel of Matthew (Grand Rapids: Baker Books, 2001), 79.
 The so-called “antitheses” of Matthew 5:21–22; 27–28; 31–32; 33–34; 38–39; 43–44 (“Ye have heard that it was said…But I say unto you”) are examples of Jesus doing ‘applied exegesis’ and exposition of the Hebrew Scriptures by utilizing the hermeneutical principle established in 5:17–20. Cf. Carson, Matthew, in Expositor’s Bible Commentary, 144.
 This was in keeping with Messianic expectation. See Isa. 2:3; Ps. 40:8; Jer. 31:31–34.
 Cf. Ps. 119:96: “Thy commandment is exceedingly broad”; Ps. 51:6: “Thou desirest truth in the inward parts”; Rom. 7:14: “The law is spiritual.”
 John Gill, An Exposition of the New Testament, vol. 1, The Baptist Commentary Series (London: Mathews and Leigh, 1809), 41; John Calvin, Commentary on a Harmony of the Evangelists Matthew, Mark, and Luke, vol. 1, 27; cf. Pseudo-Chrysostom’s comments: “The Jews would falsely accuse them of subverting the Law,” quoted in Thomas Aquinas, Catena Aurea: Commentary on the Four Gospels, Collected out of the Works of the Fathers: St. Matthew, ed. John Henry Newman, vol. 1 (Oxford: John Henry Parker, 1841), 166.
 Martin Luther, Luther’s Works, Vol. 21: The Sermon on the Mount and the Magnificat, ed. Jaroslav Jan Pelikan, Hilton C. Oswald, and Helmut T. Lehmann, vol. 21 (Saint Louis: Concordia Publishing House, 1999), 67.
 Our whole Old Testament is in view. See Craig Blomberg, Matthew, vol. 22, The New American Commentary (Nashville: Broadman & Holman Publishers, 1992), 103.
 BDAG, 522.
 Grant R. Osborn, Matthew, Zondervan Exegetical Commentary on the New Testament (Grand Rapids: Zondervan, 2010), 182; Carson, Matthew, in Expositor’s Bible Commentary, 142–43.
 Carson, Matthew, in Expositor’s Bible Commentary, 143–44.
 The πληρόω formulas are found in Matthew 2:15, 17, 23; 4:14; 8:17; 12:17; 13:35; 21:4; 26:54, 56; 27:9.
 Carson errs by limiting the meaning to prophetic fulfillment alone. For an exegetical response, see Greg Welty, Eschatological Fulfilment and the Confirmation of Mosaic Law (https://berbc.org/Library/Eschatological%20Fulfilment%20and%20the%20Confirmation%20of%20Mosaic%20Law%20-%20Greg%20Welty.shtml#FN3, accessed October 16, 2019). It is noteworthy that other New Testament passages use πληρόω for rendering obedience to the moral law (Rom. 8:3; 13:8).
 William Perkins teaches multiple levels of fulfillment: “Christ fulfills the law in three ways: by His doctrine; in His person; and in men.” He then expands these categories to include broad Christological fulfillment according to the entire witness of the New Testament. Though he arrives at this a bit differently, my interpretation is not very different from Perkins’s. See William Perkins, The Works of William Perkins, Vol. 1, ed. J. Stephen Yuille (Grand Rapids: Reformation Heritage Books, 2014), 245. Cf. the insightful comments attributed to Dr. Wordsworth: “Christ fulfilled the law and the prophets by obedience, by accomplishment of types, ceremonies, rites, and prophecies, and by explaining, spiritualizing, elevating, enlarging, and perfecting the moral law, by writing it on the heart, and by giving grace to obey it, as well as an example of obedience, by taking away its curse; and by the doctrine of free justification by faith in Himself, which the law prefigured and anticipated, but could not give.” John Peter Lange and Philip Schaff, A Commentary on the Holy Scriptures: Matthew (Bellingham, WA: Logos Bible Software, 2008), 109. I take issue with the language of “perfecting” the moral law since it has always been “perfect” (Rom. 7:12) and immutable, but the gist of his comments is a point well taken. Whatever he means by “perfecting” the moral law, he does not appear to mean that it was essentially changed, for he admits that same moral law under the old covenant is written on the heart of the redeemed by Christ in the new covenant (cf. Jer. 31:33).
 On the preservation of Scripture, see Francis Turretin, Institutes of Elenctic Theology, ed. James T. Dennison Jr., trans. George Musgrave Giger, vol. 1 (Phillipsburg, NJ: P&R Publishing, 1992–1997), 2:5.3-8 (71–72).
 Craig S. Keener, The IVP Bible Background Commentary: New Testament (Downers Grove, IL: InterVarsity Press, 1993), Mt 5:18.
 Cf. The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Mt 5:19: “whoever relaxes one of the least of these commandments…”
 Keener, The IVP Bible Background Commentary: New Testament, Mt 5:19.
 Those in our day who disregard the Lord’s Day Sabbath should take this to heart.
 An excellent explanation of what this entails can be found in Jonathan Edwards, “Christians under Special Obligations to Be Universally Holy,” in Jonathan Edwards Sermons, ed. Wilson H. Kimnach (New Haven, CT: The Jonathan Edwards Center at Yale University, 1726), 1 Pe 1:15.
 Contra Perkins, The Works of William Perkins Vol. 1, 253, who takes “the least in the kingdom of heaven” to be the unconverted who sins willfully though among the number of the professing people of God.
 Leon Morris, The Gospel according to Matthew, The Pillar New Testament Commentary (Grand Rapids, MI; Leicester, England: W.B. Eerdmans; Inter-Varsity Press, 1992), 110.
 J. C. Ryle, Expository Thoughts on Matthew (New York: Robert Carter & Brothers, 1860), 37–39.