From a Biblical standpoint, the sacrifice of blood was needed in the Old Covenant as a temporary substitute for what Jesus would eventually do on the cross. God Himself killed an animal after Adam & Eve sinned against Him, so they would have clothing upon leaving the Garden and wouldn't suffer from the elements. It was also a personal reminder that sin is no slight matter to God, but a very serious one. Many years later, when Cain committed the first murder against his brother Abel, God chastised him, saying "your brother's blood calls out to Me from the ground!" The clear meaning is that sin eventually manifests in death...and to save one means sacrificing another.
As the eternal Son of God, Jesus was able to take in 3 days an eternity of punishment for every sin all humanity had or ever would commit. That resulted in Him being briefly separated from God, and the pain is why He cried out, "Why have You forsaken Me?" It was a rhetorical question, as Jesus already knew the answer: God is pure, and sin has no place in his presence. When Jesus rose again, the punishment and restoration were completed. God's wrath and justice were satisfied forever, regarding all who were loyal to Him through His Son. Those who are not will, in the end, receive the same punishment Jesus did...but since they aren't divine, the penalty is eternal.
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God, guns, and guts made America; let's keep all three.