Deuteronomy 31:19-26

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. 21And when many disasters and calamities come on them, this song will testify against them, because it will not be forgotten by their descendants. I know what they are disposed to do, even before I bring them into the land I promised them on oath.” 22So Moses wrote down this song that day and taught it to the Israelites. 23The Lord gave this command to Joshua son of Nun: “Be strong and courageous, for you will bring the Israelites into the land I promised them on oath, and I myself will be with you.” 24After Moses finished writing in a book the words of this law from beginning to end, 25he gave this command to the Levites who carried the ark of the covenant of the Lord: 26“Take this Book of the Law and place it beside the ark of the covenant of the Lord your God. There it will remain as a witness against you.