Deuteronomy 31:19, 21, 26

“Now therefore, write this song for yourselves, and teach it to the sons of Israel; put it on their lips, so that this song may be a witness for Me against the sons of Israel.

Then it shall come about, when many evils and troubles have come upon them, that this song will testify before them as a witness (for it shall not be forgotten from the lips of their descendants); for I know their intent which they are developing today, before I have brought them into the land which I swore.”

“Take this book of the law and place it beside the ark of the covenant of the LORD your God, that it may remain there as a witness against you.