"We talk about God’s wisdom, which has been hidden as a secret. God determined this wisdom in advance, before time began, for our glory.  It is a wisdom that none of the present-day rulers have understood, because if they did understand it, they would never have crucified the Lord of glory!" ~ 1 Co 2:7–8. CEB

If satan would have known that Christ crucified would be the salvation of all mankind, he would have stopped it. That is why God kept it a secret through the ages. No one knows why God demands blood sacrifice for atonement; His wisdom is greater than man's.