Would it have been all right if Muhammad was Jewish?

Answer 1

I assume by "alright", the question is asking whether Jews would have accepted Mohammed if he were Jewish with all else being the same. This means that he would preach the same message, reveal the same Qur'an, etc. The answer is: No.

This is a common canard that Muslims bring up to justify the conflict between Mohammed and the Muslims on the one hand and the Jews of Medina (especially Banu Qurayza and Banu Qaynuqa) on the other. If the Jews would have been incapable of accepting a Messiah from outside of their group, then the conflict was inevitable.

In reality, Jews did not object to living in a Mohammed-ruled Medina (i.e. the political issue); only the requirement that they abandon their beliefs to accept him as a Divine Prophet (i.e. the religious issue).

Can Non-Jews Be Prophets?

According to Judaism, both Jews and non-Jews can be prophets. It happens that the majority of God-prophets were from the Israelite-Jewish Line because The Bible is mostly about them. One example of a Prophet in the Bible who clearly received Divine Messages but was not Jewish was Balaam (Numbers Ch. 22-24). Although he was opposed to the Jewish people, his prophecies are still considered valid. His blessing over the Jewish people is still recited in synagogues (called "Ma Tovu").

Issues with Mohammed's Prophecy

The issue with Mohammed's prophecy, from a Jewish perspective, comes from four major objections to what he claimed and preached:

Prophecy Post-Malachi: Judaism believes that each generation has a weaker connection to God than the previous generation, a concept called Yeridat ha-Dorot (ירידת הדורות). Judaism also holds that a person has to have a naturally strong connection to God to prophesy. Therefore, around the time of the Prophet Malachi, humanity was losing the strength to maintain prophesy. Jews therefore claim that since Malachi, no person is capable of prophesying successfully. As Mohammed lived over 900 years after Malachi died, Mohammed, therefore, could not be a Prophet.

Disagreements with the Torah: Mohammed claimed that he received Divine Revelations that explicitly contradicted the Torah such as the claim the Ishmael was taken to be sacrificed instead of Isaac. Mohammed claimed that any differences between what his revelations and the Torah was due to corruption from bad Jews. This infuriated Jews who maintained that their scripture was the same one that they had been using for centuries. He was disagreeing with the words of the Torah and according to Deuteronomy 13:1-4, anyone who openly disagrees with the words of the Torah is a false prophet at best.

Inclusion of Christian Tradition: Mohammed said that Jesus and John the Baptist were prophets when the Jews did not believe so. Jesus was seen in the Jewish community as not only a heretic, but the cause of much Jewish suffering in the Byzantine Empire because of its Christian orientation. They would not accept the religious leadership of someone that supported Jesus as a legitimate prophet. Of course, Jews also rejected Jesus for substantial religious reasons which Mohammed did not take the time to hear out. Muslims today often do not know what the Jewish perspective was on Jesus either that led to their rejection of him. (A related question below addresses that particular issue: Why Jews rejected Jesus?)

Different Rules: Islamic Law was not the same as Jewish Law. While there were certainly similarities, it was a different law and Jews were not going to give up their traditions and history to join a new religious group. To many Jews, it was a reflection of all of the previous religions that had tried to convert them away from their proper mission.