Moses
Deuteronomy 8:19BSB·traditional attribution

If you ever forget the LORD your God and go after other gods to worship and bow down to them, I testify against you today that you will surely perish.

Matthew Henry Presbyterian @wholebiblehenry

Moses, having mentioned the great plenty they would find in the land of Canaan, finds it necessary to caution them against the abuse of that plenty, which was a sin they would be the more prone to new that they came into the vineyard of the Lord, immediately out of a barren desert. I. He directs them to the duty of a prosperous condition, Deu 8:10.

Commenting on Deuteronomy 8:10-20

John Gill Reformed Baptist @doctorgill

As the nations which the Lord destroyeth before your face, so shall ye perish,.... Be cut off by the sword, or cast out as they were, the same sins, particularly idolatry, being committed by them. This is to be understood of the seven nations of the land of Canaan, which the Lord would be gradually destroying when Israel came into the possession of their land...

Geneva Bible Notes Reformed @genevanotes

And it shall be, if thou do at all forget the LORD thy God, and walk after other gods, and serve them, and worship them, I testify against you this day that ye shall surely perish. (k) Or take to witness the heaven and the earth, as in .