Deuteronomy 31:19-21

19Now therefore write athis song and bteach it to the people of Israel. Put it in their mouths, that this song may be ca witness for me against the people of Israel. 20For when I have brought them into the land dflowing with milk and honey, which I swore to give to their fathers, and they have eaten and are full and egrown fat, fthey will turn to other gods and serve them, and gdespise me and hbreak my covenant. 21And when many evils and troubles have come upon them, this song shall confront them as ia witness (for it will live unforgotten in the mouths of their offspring). For jI know what they are inclined to do even today, before I have brought them into the land that I swore to give.”
Copyright information for ESV