Deuteronomy 31:21-25

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

So Moses wrote down this song on the same day, and taught it to the sons of Israel. Joshua Is Commissioned

Then He commissioned Joshua the son of Nun, and said, “Be strong and courageous, for you will bring the sons of Israel into the land which I swore to them, and I will be with you.”

It came about, when Moses finished writing the words of this Law in a book until they were complete,

that Moses commanded the Levites who carried the ark of the covenant of the Lord, saying,