This is what God said to him: ‘Your descendants will live in a foreign country, where they will be slaves and will be badly treated for four hundred years.
The Lord said to him, “Your descendants will be strangers in a foreign land; they will be slaves there and will be treated cruelly for four hundred years.
What I mean is that God made a covenant with Abraham and promised to keep it. The Law, which was given four hundred and thirty years later, cannot break that covenant and cancel God's promise.
It will be four generations before your descendants come back here, because I will not drive out the Amorites until they become so wicked that they must be punished.”