Aaron’s career was twofold – as careful keeper of the ritual procedures of the sanctuary, and as counsellor and peace-maker for his community. According to Rashi, the whole of the people mourned him because they had all gained from his ministrations.
Moses was the public figure, the intellectual, the prophet who gave the people leadership. Aaron was the pastor who brought a spirit of joy, harmony and reconciliation to the people to such an extent, say the Talmudic sages (Rosh HaShanah 3a), that when he died the clouds of glory dissipated.
Aaron was a great man but so was Moses, and the sages tell us that the brotherly spirit that bound them together was not merely because of shared lineage but because they appreciated each other.
History records many cases of kin’at sof’rim, jealousy between colleagues, but Moses and Aaron were prototypes of Psalm 85:11, “Mercy and truth have met together: righteousness and peace have kissed one another”.