Deuteronomy 31:21-23

31:21 Then when many disasters and distresses overcome them this song will testify against them, for their descendants will not forget it. I know the intentions they have in mind today, even before I bring them to the land I have promised.” 31:22 So on that day Moses wrote down this song and taught it to the Israelites, 31:23 and the Lord commissioned Joshua son of Nun, “Be strong and courageous, for you will take the Israelites to the land I have promised them, and I will be with you.”