Moshe spoke about the time when the Israelites came to the land, and they would follow certain actions and traditions. One that he mentioned was that “Your G-d will raise up a prophet from your midst, from among your bretheren, like myself; you shall listen to him”.
R’ SR Hirsch wrote that it was not the purpose of the prophets to take the place of magicians or soothsayers. The need for such practitioners had already been ruled out, and R’ Hirsch wrote that a prophet is not sent so that we can consult him about the feasibility of our plans; his purpose is not to satisfy our thirst for knowledge ordinarily denied to man. G-d sends us His prophet in order that he, the prophet may tell us what G-d wishes us to know. The prophet is not our instrument, but he is the instrument of G-d. The verse says “you should obey him” not consult him.
Moshe said that the prophets that G-d would send would be people from “your midst” meaning that they would live with the people and not be surrounded by an aura of mystery. The Israelites would know the prophet’s parents, and family, and the prophet would be an ordinary human being, and not seek to be anything more than that. G-d would raise him up and enable him to stand tall, so that he would be trusted by the Israelites, and so that his authority would be established as G-d’s emissary.
R’ Hirsch wrote that if a prophet proclaims that a single mitzvah of the Torah is to be abrogated, he is not to be obeyed and it is a capital offence. If a prophet who is already proven and established as a prophet demands an action which goes beyond the Torah laws, as Eliyahu did on Mt Carmel, he should be obeyed. A prophet could be authenticated by the occurrence of a miracle that was predicted or by the realisation of an announcement of what would happen in the future.