Hebrews 11:17-20

By faith Abraham, when God tested him, offered Isaac as a sacrifice. He who had embraced the promises was about to sacrifice his one and only son, even though God had said to him, “It is through Isaac that your offspring will be reckoned.” Abraham reasoned that God could even raise the dead, and so in a manner of speaking he did receive Isaac back from death. By faith Isaac blessed Jacob and Esau in regard to their future.