Deuteronomy 31:20-21

20When I have brought them to the land flowing with milk and honey, of which I swore to their fathers, and they have eaten and filled themselves and grown fat, then they will turn to other gods and serve them; and they will provoke Me and break My covenant.

21Then it shall be, when many evils and troubles have come upon them, that this song will testify against them as a witness; for it will not be forgotten in the mouths of their descendants, for I know the inclination of their behavior today, even before I have brought them to the land of which I swore to give them.”