Well the law was to prove how we needed Christ. However, in the 2nd temple period, the Pharisees added things for the purpose of their greed and control, that were never given by Moses.
As I stated, Jesus chastised them for it.
Mind you, God told us NOT to change what He ordained. The Pharisees did a lot more than just change it, they created whole new laws God never imposed.
Now when Christ came, He was God incarnate and He fulfilled the laws we could not. Jesus was the perfect lamb who never ever broke any of the comandments. Thus the reason His sacrifice was sufficient for our sins, IF, we accept and believe in Him as our Lord and Savior.
I also want to add, that in all that some tribes changed, and even Moses allowance for divorce, they were not condoned by God.
True, men always created grey areas where God uses black and white with no middle grey area.
We are constantly looking for loopholes, but try as we may, or do as we do, there are none.
Thus the reason Jesus told His disciples that man cannot, which proved we needed a perfect forever Sacrifice as the mediator..
However, Jesus wants us to live with our errors by asking for forgiveness, and trying harder to be right. Instead of creating grey areas to justify our weaknesses.