The word fulfill means to "fill out, expand, or complete". This did not mean to end the law. This next statement may seem to contradict the definiton I just gave you, but by the end of this study, all will make sense.
In the following Scriptures, we can see that the law was temporary:
"For Christ is the end of the law for righteousness to everyone who believes." Romans 10:4
The word end in this particular passage can mean "fulfillment" and Christ was the fulfillment of all of the requirements of the law. This same word can mean "goal" and the law was in place to recognize our need for our Savior, Jesus Christ. He was the "goal and fulfillment" of the law.
"having abolished in His flesh the enmity, that is, the law of commandments contained in ordinances, so as to create in Himself one new man from the two, thus making peace, and that He might reconcile them both to God in one body through the cross, thereby putting to death the enmity." Ephesians 2:15-16
Through Christ, the righteous standards of the law that could never be reached reached by us, were now satisfied. Simply stated, believers fulfill the law because of Christ's work on the Cross.
"For the priesthood being changed, of necessity there is also a change of the law." Hebrews 7:12
By Scripture itself, we have seen that the law (as it was) was temporary. It was not done away with, but fulfilled through Christ.
We are about to see that it is eternal as well.
"21:But now the righteousness of God set apart from the law is revealed, being witnessed by the Law and the Prophets,
31:Do we then make void the law through faith? Certainly not! On the contrary, we establish the law." Romans 3:21, 31
The phrase "the righteousness of God" in v. 21 refers the act of God in which He declares a sinner righteous.
"For what the law could not do in that it was weak through the flesh, God did by sending His own Son in the likeness of sinful flesh, on account of sin: He condemned sin in the flesh, that the righteous requirement of the law might be fulfilled in us who do not walk according to the flesh but according to the Spirit." Romans 8:3-4
The law in itself, could not do anything to rid a person's life of sin. Only repentance and faith in Christ, the sacrifice for our sin, could save us from our sin.
19: "Whoever therefore breaks one of the least of these commandments, and teaches men to do 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."
"For whoever shall keep the whole law, and yet stumble in one point, he is guilty of all."James 2:10,
Following the law of God, is showing obedience. We do not have the option of being "cafeteria Christians" picking and choosing what parts of the law we repent over when we have sinned.
20: "For I say to you, that unless your righteousness exceeds the righteousness of the scribes and Pharisees, you will by no means enter the kingdom of heaven."
We see in this last Scripture why Christ is telling us that our righteousness must exceed that of the Scribes and Pharisees. It takes having faith in Christ to attain the righteousness God gives the believer.
"For they being ignorant of God's righteousness, and seeking to establish their own righteousness, have not submitted to the righteousness of God." Romans 10:3
