Matt 5:17 "Do not think that I (Jesus) have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them.
It's filled in me through my faith in Him. Faith is what's required for a right relationship with God. Man cannot do that on his own, so God Himself came to Earth in the flesh to do it for us and said that if we accept by faith what was done, then we would be righteous.
Hebrews 11:6And without faith it is impossible to please God, because anyone who comes to him must believe that he exists and that he rewards those who earnestly seek him.
Galatians 3:6 Consider Abraham: "He believed God, and it was credited to him as righteousness."
The law hasn't changed. Those are God's standards for us, they always have been. The requirement to live by them no longer applies but that doesn't mean the truth of them has changed.
How, for example, were the laws against cattle breeding, sowing fields with two kinds of seed, and wearing clothes of mixed linen and wool fulfilled in Christ?
And were the laws against homosexuality also fulfilled in Christ, and hence don't need to be followed any longer? How about the laws against defiling your daughter by making her a prostitute? Fulfilled? Don't need to be followed anymore?
The law hasn't changed. Those are God's standards for us, they always have been. The requirement to live by them no longer applies but that doesn't mean the truth of them has changed.
If these laws remain true, why aren't we required to live by them? Because they aren't "as true" today?