Deuteronomy 31:16

31:16 Then the Lord said to Moses, “You are about to die, and then these people will begin to prostitute themselves with the foreign gods of the land into which they are going. They will reject me and break my covenant that I have made with them.

Deuteronomy 31:20

31:20 For after I have brought them to the land I promised to their ancestors – one flowing with milk and honey – and they eat their fill and become fat, then they will turn to other gods and worship them; they will reject me and break my covenant.