This may not be the board for this but i'm new & can only post here.
I may be wrong about this but the scriptures about it tell me reasons why but not the reasons for the reasons why, answers just lead to more question.
I've been asking myself this question for a long time now and this is the only conclusion I've come up so far tell me if i'm wrong.
Question: Why does God require sacrifice in order to forgive sin, why can't he just forgive us freely, why sacrifice his son?
Answer: I think God could forgive us freely but we would be unable to forgive ourselves we wouldn't be able to stand before the Lord with all our shame & for us not to accept Jesus as a sacrifice for our sins would be a slap to his face & and I don't want to slap Jesus, thus forcing our hand. God didn't require a sacrifice we did.