Moses
Deuteronomy 18:21BSB·traditional attribution

You may ask in your heart, “How can we recognize a message that the LORD has not spoken?”

John Calvin Reformed @genevareformer

21. And if thou say in thy heart. This exception has reference to the prohibition, which we have already noticed in this same chapter. God, in His appointment of Prophets to be His substitutes in teaching the people, had invested them with no common authority, enjoining obedience to be paid to their precepts.

Matthew Henry Presbyterian @wholebiblehenry

Here is, I. The promise of the great prophet, with a command to receive him, and hearken to him. Now, 1. Some think it is the promise of a succession of prophets, that should for many ages be kept up in Israel.

Commenting on Deuteronomy 18:15-22

John Gill Reformed Baptist @doctorgill

When a prophet speaketh in the name of the Lord,.... Says he comes from God, is sent by him, and has a commission from him to say so: if the thing follow not, nor come to pass; as the prophecy of Hananiah, Jer 28:3 that is the thing which the Lord hath not spoken; or otherwise it would have come to pass, unless when a...