I assume no such thing. I see no difference between how God was in the Old versus the New Testament. God does not change. My argument with Joe is that a perfect sacrifice was required by God's perfect Justice. I've also stated quite clearly, I thought, that God looks at the heart of man, and must see repentance before mercy is dispensed. I'm not sure how much clearer I can make it than I have already.
Since God is Holy, He will not abide sin in His presence. Thus the need for the Lamb without Blemish to satisfy God's law that demands death for sin. "The soul that sinneth, it shall die." Ez. 18:20. That's what God says. In order to pay that requirement of God's law, Jesus had to come. Now, what is your argument with that. I've been arguing with Joe about that for pages and pages. So, you tell me. What's the problem?