Dear Rabbi, Im an Italian ben Noach. I read the Mishneh Torah, Foundations of the Torah 9:1, where Rambam writes that a prophet cannot add a new mitzvah or change the present mitzvot etc. It seems to me that according to Rambams teachings the part that a prophet is not allowed to change is the legal part (mitzvot), but Torah doesnt have only laws but also principles of faith or statements about various beliefs (resurrection, Messiah, etc.). My impression is that also the non legal parts are immutable. Indeed, as Rabbi Tovia Singer said, all the prophets after Moses didnt add or change anything, they just added more details about topics already present in the Torah (the resurrection, messianic age etc. are already in the books of Moses). But these details never changed the main content of this teachings. So for example, if a prophet came and said that only the Jews with black hair will resurrect from the dead (that is not a detail) we wouldnt allowed to believe him, even if he performs miracles. Is my impression wrong?

Shalom, Thank you for your question. Yes, your understanding is correct. Generally, (with only very special minor exceptions) a prophet cannot change the basic principles of the Torah. I hope this answer is of some help. Feel free to write back with any follow-up questions. Many blessings.