Why does God not just abolish the law? Without the law, the fault of sin is not attributed to anyone,* but a just** God cannot allow sin to simply exist without attributing it to someone and punishing them. So now “the Law came in so that the transgression would increase; but where sin increased, grace abounded all the more.”# And so justification before the law is possible without injustice, through grace, for we can become “justified as a gift by His grace through the redemption which is in Christ Jesus”## Abolishing the law would mean God was unjust, so instead he offers justification as a gift, and our sins are imputed to Christ.
So Jesus came to fulfill in the sense of completing the law. The law was sent to increase sin, and therefore increase grace. Jesus was sent to be a propitiation for the sins of the whole world^ and allow grace to begin, thus completing the purpose of the law. So not a single bit of the law will become void until heaven and earth pass away;^^ We all remain guilty before the law until the end of days except for the grace of Jesus.
*Romans 5:13 “For until the Law, sin was in the world, but sin is not imputed when there is no law.”
**“Consistent with what is morally right; righteous: a just cause.” The American Heritage Dictionary of the English Language, Fourth Edition
^1 John 2:2 “and He Himself is the propitiation for our sins; and not for ours only, but also for those of the whole world.”
^^Matthew 5:18 “For truly I say to you, until heaven and earth pass away, not the smallest letter or stroke shall pass from the Law until all is accomplished.”