Maharal(Gevuros HaShem): Why didn’t Moshe marry a Jewish woman from birth with pedigree like Aaron? Don’t think like the fools that this just happened because that is mistakenly dismissing foundation principles. Therefore it is important to explain itdsf because this is one of the reasons that Moshe’s children were inferior to Aaron’s children. From here our Sages (Bava Basra 109b) learned that one should always attach oneself with a pedigreed family. If so what was the reason that he married a woman from another nation? This is truly a very great question but if you think about it intelligently you will realise it was not done for nothing but was for a extremely important issue. Firstly you should know that Moshe was equivalent to the entire Jewish people because he was in fact the completing factor for the entire Jewish people. That is why the Torah (Shemos 18:1) writes that Yisro… heard all that G‑d had done for Moshe and for Yisroel. We thus see that Moshe is equivalent to all the entire Jewish people… Therefore it makes no sense that he would marry a woman who is one of the 600, 000 Jews when Moshe was equal to the 600,000. In contrast gerim who are outside of the Jewish people and therefore are not included in the 600,000 are capable of matching Moshe. That is because Moshe was not included in the 600,000. Thus the soul of the convert if she merited was more appropriate for Moshe who transcended the Jewish people. It is important to understand this amazing thing. Consequently Moshe married a woman from a different people even though the Jewish people are the essence of the world and the other nations are merely additions and supplements. Thus gerim when they convert become additions to the Jewish people. This is the reason that Moshe married a giyorus.