Having abolished in his flesh the enmity, even the law of commandments contained in ordinances; for to make in himself of twain one new man, so making peace; Eph.2:15
Abolishing the "enmity" of the law, that is a law, if enforced would have condemned them. Do you understand? Paul is saying that if Jesus had enforced the law, while they were sinning against him, they would be condemned.
And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world. 1Jn.2:2
Propitiation means "appeasement." God doesn't need to make appeasement with himself. He's one in himself.
The appeasement, or peace between God and man, is exemplified in the example Christ gave.
God has never been divided against himself. God is appeased by his own nature.
As an example, in Lk.13:6-9, the landowner and the caretaker aren't at odds over what to do with the fruitless tree, because God and his Son are perfectly One. They both know the fruitless tree is headed for the fire, so they agree to nurture it for one more year. It's no different from God giving the people of Noahs' day 120 years to repent.