English Explanation of Mishnah Sanhedrin 11:5

‘A false prophet’; he who prophesies what he has not heard, or what was not told to him, is executed by man.
But he who suppresses his prophecy, or disregards the words of a prophet, or a prophet who transgresses his own word , his death is at the hands of heaven, as it says, “[And if anybody fails to heed the words he speaks in my name] I Myself will call him to account (Deut. 18:19).
Mishnah five defines the “false prophet” who is executed by strangling.
Deuteronomy 18:20 states that any prophet who “presumes to speak in My name an oracle that I did not command him to utter” shall be killed. Our mishnah teaches that a false prophet is one who states a prophecy that he either did not hear at all, or that he heard from another person and not straight from God. However, a prophet who hears the words of God but does not tell others (like Jonah) or one who ignores the words of another prophet (see I Kings 20:35-36) or one who ignores even his own prophecy (see I Kings 13:26) is killed not by a human court but by God. This exegesis presents an interesting twist on the verse quoted from Deuteronomy. The simple meaning of the verse is that a member of the tribe of Israel who ignores the true words of the prophet is not to be executed by the court but God will take His own revenge. The mishnah interprets the verse to refer not to a normal person, but to the prophet himself.