Deuteronomy 31:18-22

And I will surely hide My face in that day because of all the evil which they have done, in that they have turned to other gods. “Now therefore, write down this song for yourselves, and teach it to the children of Israel; put it in their mouths, that this song may be a witness for Me against the children of Israel. When 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. Then 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.” Therefore Moses wrote this song the same day, and taught it to the children of Israel.