Jesus – the Fulfillment of the Law

Mat 5:17 Think not that I came to destroy the law or the prophets: I came not to destroy, but to fulfill. 

Mat 5:18 For verily I say unto you, Till heaven and earth pass away, one jot or one tittle shall in no wise pass away from the law, till all things be accomplished. 

Mat 5:19 Whosoever therefore shall break one of these least commandments, and shall teach men so, shall be called least in the kingdom of heaven: but whosoever shall do and teach them, he shall be called great in the kingdom of heaven. 

Mat 5:20 For I say unto you, that except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no wise enter into the kingdom of heaven. (ASV) 

Jesus says "Think not that I am come to destroy the law and the prophets". The preceding verses were so opposed to the teachings of the scribes and Pharisees that some might assert that he was a destroyer of the law. He replies that he has not come to destroy it, but to fulfill. He does not say that he has come to perpetuate it.

To fulfill means to complete its purpose. He was the end of the law. It was a "schoolmaster to bring us to Christ" (Gal 3:24), but "after faith is come we are no longer under the schoolmaster."

By the phrase "law of Moses" is meant all that was revealed through Moses. The New Testament treats it with great fullness and perspicuity:

1. Typical Aspects. The Law of Moses was only the shadow of good Things to come (Col 2:17; Heb 10:1).
2. Fulfillment. Jesus Christ declared His intention to fulfill every word of the law (Mat 5:17-18), and He did it (Luke 24:44).
3. Its Weakness. The law could not,

a. bring about justification (Act 13:39); b. produce righteousness (Gal 2:21); c. produce life (Gal 3:21); d. bring about perfection (Heb 7:19); e. or free the conscience from a knowledge of sin (Heb 10:1-4).

4. Impossible for All Men to Keep It. The law was given to and for Israel only (Exo. 19:1-20:17; Mal 4:4; Joh. 1:1-17). Take two proofs of this:

a. All the males of the Hebrews were commanded to appear before the Lord at a designated place three times a year (Exo 23:14-17; Exo 12:4-16); b. those to whom the law was given were commanded, on penalty of death, not to kindle a fire throughout their habitation on the sabbath day (Exo 35:1-3).

5. Abolishment of the Law. It is declared,

a. that the law is abolished (2Co 3:6-13; Eph 2:15); b. that Christ is the end of the law (Rom 10:4); c. that it was the ministration of death (Exo. 32:1-28), and that it is "done away" (2Co 3:7); d. that Jesus took away the first that He might establish the second (Heb 10:5-9); e. that it was nailed to the cross (Col 2:14-16); f. that those who had been under it had been delivered from it (Rom 7:6); g. that they were dead to it (Rom 7:4); h. that they were not under the law, but under grace (Rom 6:14); i. that they were no longer under the schoolmaster (Gal 3:24-25); j. that they were not required to serve the law (Act. 15:1-24; Gal 3:19); k. that the Christian who sought justification under the law had fallen from grace (Gal 5:4); l. and that now the righteousness of God is revealed without the aid of the law (Rom 3:21-22).

6. Contrasted with the Gospel.

a. The law was intended for one nation--Israel (Exo. 20:1-17 Mal 4:4); the gospel of Christ is intended for the whole creation (Mat 28:18-20; Mar 16:15-16). b. The first covenant was dedicated with the blood of animals (Exo 24:6-8), the new covenant was dedicated with the blood of Jesus Christ (1Pe 1:18-19). c. The first institution was administered by frail men--the Levites (Lev. 16:1-34; Heb 7:11-23); the second is administered by Jesus Christ, who was made priest, not by carnal commandment, but "after the power of an endless life" (Heb 7:16). d. Circumcision in the flesh was a sign of the first (Gen 17:1-14; Lev 12:1-13); circumcision in the heart and spirit is the sign of the second (Rom 2:25). e. The Law of Moses guaranteed to the obedient Hebrews temporal blessings (Deu 28:1-6); the gospel of Christ guarantees spiritual blessings to those who live up to its requirements (1Pe 1:4). f. The Law of Moses guaranteed to the Hebrews the land of Canaan (Deu 30:5-10); the gospel guarantees eternal life beyond the grave to those who honor the Lord (1Jo 5:20). g. The Law of Moses required obedience to the one true God (Exo 20:1-5); the gospel emphasizes the Fatherhood of God (Mat 6:9). h. The Law of Moses prohibited the people from taking the name of the Lord in vain (Exo 20:7); the gospel requires that out communications be "yea" and "nay", declaring that everything beyond is evil(Mat 5:37). i. The Law of Moses required the Hebrews to remember the Sabbath day (Exo 20:8-11); in apostolic times, the people of God remembered the Savior in the feast that He ordained (Mat 26:26-30; 1Co 11:23-29) on the first day of the week (Act 20:7). j. The Law of Moses required children to honor their parents (Exo 20:12); the gospel requires children to obey their parents in the Lord (Eph 6:1-4). k. The Law of Moses prohibited murder (Exo 20:13); the gospel prohibits hatred (1Jo 3:15). l. The Law of Moses forbade adultery (Exo 20:14); the gospel prohibits even lust (Mat 5:28). m. The Law of Moses prohibits stealing (Exo 20:15); the gospel prohibits stealing and requires benevolence (Eph 4:28). n. The Law of Moses forbade the bearing of false witness (Exo 20:16); the gospel requires us to speak the truth in love (Eph 4:15). o. The Law of Moses prohibited covetousness (Exo 20:17); the gospel requires us to do good unto men according to our opportunities (Gal 6:10), and love our neighbors as ourselves (Rom 13:10;

One jot or tittle. Jot means the smallest letter of the Hebrew alphabet, while tittle refers to a simple turn by which one letter is distinguished from another. The expression, "jot or tittle," was proverbial for the smallest part.

Till all be fulfilled. "Till," says Dr. Schaff, "implies that after the great events of Christ's life, and the establishment of his kingdom, the old dispensation, as a dispensation of the letter and yoke of bondage, as a system of types and shadows, will pass away, and has passed away (Eph 2:15; Col 2:14; Heb 8:13); while the spirit and substance of the law, i.e., love to God and man, will last forever."

References:
Albert Barnes, Albert Barnes' Notes on the Bible.
Ashley S. Johnson, Condensed Biblical Cyclopedia.
B. W. Johnson, The People's New Testament.
Dr. John Gill, John Gill's Exposition of the Entire Bible.