Sforno on Deuteronomy 18:22/ספורנו על דברים י״ח:כ״ב

1ולא יהיה הדבר, for when the prophet commands a “new” commandment, unless it is accompanied by a miracle attesting to his authority by G’d to do so, the fact that he failed to produced the promised miracle proves that he is a false prophet. An example of this is mentioned in Joshua in the valley of the river Jordan. (Joshua 3 when Joshua promised miracles and the people crossed the swollen Jordan river with dry feet, the waters having backed up) Also the predicted collapse of the protective wall around Jericho as the result of blasts on the shofar was such a miracle legitimising violating the Sabbath on that occasion. (Joshua 6) In the case of the prophet Elijah at Mount Carmel, the heavenly fire descending and consuming his offering on the rebuilt altar, as well as the water in the surrounding moat, proved that he had acted with G’d’s approval, was totally authentic. (Kings I 18,38) Concerning the reverse, a prophet being punished for failing to carry out the instructions of his colleague, an example is found in Kings I 20,35-36. Were this not so, why would someone be punished for not inflicting physical hurt on his fellow man?