Or HaChaim on Numbers 12:2/אור החיים על במדבר י״ב:ב׳

1 הרק אך במשה דבר ה׳?? "Did G'd speak to Moses exclusively?" Our sages in Bereshit Rabbah 1,14 and Jerusalem Talmud Berachot 9,7 have said that every time the words אך or רק appear they are restrictive in character. In this instance we can also detect that both words are meant as some kind of restrictive clause. Miriam and Aaron felt that the fact that Moses had abandoned normal family relations with his wife was a silent accusation against them who continued to maintain regular marital relations with their respective spouses. Sifri takes the same line expanding Miriam's complaint by accusing Moses of criticising the patriarchs by his refusal to maintain family relations with his wife. Miriam and Aaron felt it also was an act of arrogance vis-a-vis our patriarchs all of whom G'd had communicated with, and who had not stopped living normal married lives with their spouses because G'd had addressed them from time to time. Did Moses pretend to be more pious than the patriarchs? On the other hand, it is possible that Miriam and Aaron alluded to two deficiencies in Moses as a prophet. 1) Moses never began his career as a prophet until he attained the age of 80 as we know from Exodus 7,7, whereas she, Miriam, as well as Aaron had already been given prophetic powers at the age of 3, prior to Moses' birth. 2) Moses' second deficiency conisted in the fact that on the very day he was appointed as a prophet he contracted the dread disease of Tzoraat indicating he had been found wanting in the eyes of G'd (Exodus 4,6). Neither Miriam nor Aaron had ever been afflicted with that disease. The words אך and רק in our verse refer to these two deficiencies Miriam and Aaron perceived in Moses.

2וישמע השם. G'd heard. The Torah had to write these words [although we know that G'd hears every word spoken by anyone Ed.] to tell us that Miriam and Aaron did not say what they said within earshot of any other creature [a third party which was not involved. Ed.]. Another reason the Torah wrote these words is to tell us that G'd heard this directly from Miriam and Aaron and not as a complaint from Moses. Moses did not complain to G'd about having been slighted.