During His ministry Jesus Christ made the claim that he came to fulfill the Law.

Mat 5:17  “Do not think that I came to destroy the Law or the Prophets. I did not come to destroy but to fulfill [pleroo].
Mat 5:18  For assuredly, I say to you, till heaven and earth pass away, one jot or one tittle will by no means pass from the law till all is fulfilled.

The Greek word translated “fulfill” in verse 17 is pleroo, which means to make full, to bring to completion.  Christ fulfilled the law, not by abolishing it, otherwise verse 19 where Jesus commands us to do (keep) the law makes no sense. 

Mat 5:19  Whoever therefore breaks one of the least of these commandments, and teaches men so, shall be called least in the kingdom of heaven; but whoever does and teaches them, he shall be called great in the kingdom of heaven.

How then did Christ fulfill the law?  Christ fulfilled the law primarily in two ways by:

1. Magnifying the Law
2. His Death

We now explain this is more detail.

1)  Christ fulfilled the law by magnifying it.

Christ magnified the law by teaching obedience to the spirit of the law, not just the letter. 

Mat 5:21  “You have heard that it was said to those of old, ‘YOU SHALL NOT MURDER, and whoever murders will be in danger of the judgment.’
Mat 5:22  But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment. And whoever says to his brother, ‘Raca!’ shall be in danger of the council. But whoever says, ‘You fool!’ shall be in danger of hell fire.

Christ magnified the command, do not murder, by teaching do not hate.

Mat 5:27  “You have heard that it was said to those of old, ‘YOU SHALL NOT COMMIT ADULTERY.’
Mat 5:28  But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart.

Christ magnified the command, do not commit adultery, by teaching do not lust.

Christ magnified the law (the ten commandments) governing behaviour to expand to our thoughts.  Christ taught we must control our thoughts, not just our actions.

Jesus Christ’s magnification of the law was written about by the prophet Isaiah.

Isa 42:21  The LORD is well pleased for His righteousness’ sake; He will exalt the law and make it honorable.

Isa 42:21 The LORD is well pleased for his righteousness’ sake; he will magnify the law, and make it honourable. (KJV)

2)  Christ fulfilled the law by His death

Christ’s death fulfilled the law in several ways.

Christ’s death fulfilled the law by ending the Old Covenant: its animal sacrifices and its priesthood.

Christ’s sacrifice superseded all animal sacrifices, thus ending the need for them.

Heb 10:8  Previously saying, “SACRIFICE AND OFFERING, BURNT OFFERINGS, AND OFFERINGS FOR SIN YOU DID NOT DESIRE, NOR HAD PLEASURE IN THEM” (which are offered according to the law),
Heb 10:9  then He said, “BEHOLD, I HAVE COME TO DO YOUR WILL, O GOD.” He takes away the first that He may establish the second.
Heb 10:10  By that will we have been sanctified through the offering of the body of Jesus Christ once for all.
Heb 10:11  And every priest stands ministering daily and offering repeatedly the same sacrifices, which can never take away sins.
Heb 10:12  But this Man, after He had offered one sacrifice for sins forever, sat down at the right hand of God,
Heb 10:13  from that time waiting till His enemies are made His footstool.
Heb 10:14  For by one offering He has perfected forever those who are being sanctified.

We have access to Jesus Christ as our High Priest. 

Heb 3:1 Wherefore, holy brethren, partakers of the heavenly calling, consider the Apostle and High Priest of our profession, Christ Jesus;

Heb 4:14 Seeing then that we have a great high priest, that is passed into the heavens, Jesus the Son of God, let us hold fast our profession.

The Levitical priesthood was brought to completion.

Heb 7:11  Therefore, if perfection were through the Levitical priesthood (for under it the people received the law), what further need was there that another priest should rise according to the order of Melchizedek, and not be called according to the order of Aaron?
Heb 7:12  For the priesthood being changed, of necessity there is also a change of the law.

Heb 7:23  Also there were many priests, because they were prevented by death from continuing.
Heb 7:24  But He, because He continues forever, has an unchangeable priesthood.
Heb 7:25  Therefore He is also able to save to the uttermost those who come to God through Him, since He always lives to make intercession for them.
Heb 7:26  For such a High Priest was fitting for us, who is holy, harmless, undefiled, separate from sinners, and has become higher than the heavens;
Heb 7:27  who does not need daily, as those high priests, to offer up sacrifices, first for His own sins and then for the people’s, for this He did once for all when He offered up Himself.
Heb 7:28  For the law appoints as high priests men who have weakness, but the word of the oath, which came after the law, appoints the Son who has been perfected forever.

Christ’s death fulfilled the law by ending the need for the physical temple.

Through the Holy Spirit God now dwells in true believers rather than a physical temple.

Isa 57:15  For thus says the High and Lofty One Who inhabits eternity, whose name is Holy: “I dwell in the high and holy place, With him who has a contrite and humble spirit, To revive the spirit of the humble, And to revive the heart of the contrite ones.

1Co 3:16  Do you not know that you are the temple of God and that the Spirit of God dwells in you?
1Co 3:17  If anyone defiles the temple of God, God will destroy him. For the temple of God is holy, which temple you are.

Eph 2:19  Now, therefore, you are no longer strangers and foreigners, but fellow citizens with the saints and members of the household of God,
Eph 2:20  having been built on the foundation of the apostles and prophets, Jesus Christ Himself being the chief cornerstone,
Eph 2:21  in whom the whole building, being fitted together, grows into a holy temple in the Lord,
Eph 2:22  in whom you also are being built together for a dwelling place of God in the Spirit.

Christ’s death fulfilled the law by ending the need for physical circumcision.

Circumcision of the flesh is not longer required.  True circumcision is that of the heart, a repentant attitude.

Rom 2:28  For he is not a Jew who is one outwardly, nor is circumcision that which is outward in the flesh;
Rom 2:29  but he is a Jew who is one inwardly; and circumcision is that of the heart, in the Spirit, not in the letter; whose praise is not from men but from God.

1Co 7:19 Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of God.

Col 2:11  In Him you were also circumcised with the circumcision made without hands, by putting off the body of the sins of the flesh, by the circumcision of Christ,