Why would God give the Law, punish those who did not obey it, and then supposedly rescind the Law? If the Law was that important to give us in the first place, then did He make a colossal mistake in doing so? And why would it say in the scriptures that the Law is "forever" and "perpetual"? Is He prone to lying?
First. lets address "the law" , as applies to the Jews. Jews do not keep the law as it was originally given in the Torah. The Talmudic tradition of the law, developed in the first century AD, eliminated and changed many parts of the law. As an example, I know of no Jewish communities that sacrifice animals,or Jews that segregate menstruating women during their time. So, Judaism itself has changed the law.
As for Christians , As I have said elsewhere, quoting Christ, he has fulfilled the law. What did he mean ? One of the definitions of fulfill is to "satisfy". If I murder someone, the law identifies my crime and demands my capture. The law demands I have a trial, when convicted, the law demands my punishment, when I am executed, the law is fulfilled, satisfied. It is impossible for the law to have any more effect on me. For me, the law ceases to exist.
Now then, we all are guilty of heinous crimes before the law of the Torah. We all deserve death for these crimes. Christ, in our place, lived the law perfectly totally without sin, through him we have and will be sinless before the law. The punishment for those crimes that we deserve before the law, he received, his death, was ours. All the demands of the law are totally fulfilled. In his death, we are dead to the law, it can have no further authority over us. The law still exists, it is forever, and those who put themselves under it, rejecting Christ's substitute live and death, must attempt to follow it, and receive it's punishments. For the Christian, there is a new law, as Paul said, "he who loves his neighbor has fulfilled the law " To paraphrase Martin Luther, " in Christ, it is as if I lived his life, breathed his breath, lived his life, suffered his pain, experienced his crucifixion, died his death, and was raised with him from the dead".
