Moses
Deuteronomy 31:30ESV·traditional attribution

Then Moses spoke the words of this song until they were finished, in the ears of all the assembly of Israel:

Matthew Henry Presbyterian @wholebiblehenry

Here, I. The charge is given to Joshua, which God has said (v. 14) he would give him. The same in effect that Moses had given him. The same in effect that Moses had given him (v. 7): Be strong and of a good courage, v. 23.

Commenting on Deuteronomy 31:22-30

Read all of Deuteronomy 31 (ESV)
Read Deuteronomy 31:30 in the BSB