Deuteronomy 31:19-20

19“Now write down this song and teach it to the Israelites and have them sing it, so that it may be a witness for me against them. 20When I have brought them into the land flowing with milk and honey, the land I promised on oath to their ancestors, and when they eat their fill and thrive, they will turn to other gods and worship them, rejecting me and breaking my covenant.