Deuteronomy 31:19-22

19And now, write ye this song, 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.

20For I shall bring them into the land which I swore unto their fathers, which floweth with milk and honey; and they will eat and fill themselves, and wax fat, and will turn unto other 1gods, and serve them, and despise me, and break my covenant.

21And it shall come to pass, when many evils and troubles have befallen them, that this song shall testify against them as a witness; for it shall not be forgotten out of the mouths of their seed; for I know their imagination which they are forming already this day, before I bring them into the land which I have sworn [unto them].

22And Moses wrote this song the same day, and taught it to the children of Israel.