Aaron had escaped the death sentence of the Pharaoh by being just old enough not to fall under its judgment. But Moishe had been the right age and was, therefore, condemned to death. Their mother--Jochebed--secreted him away and freed him from his death sentence by secretly giving him over into the hands of those close to the Pharaoh. Moishe was far away. He was not geographically distant from his true family but, rather, he was ideologically miles away as he grew up in affluence and wealth under the care of the daughter of the Pharaoh.
They had tried to keep Aaron from finding out about brother Moishe's fate because they were worried that he might reveal their family's deep and cherished secret--one of their own sat in the lap of Mitzrayim (Egypt). It was better, they thought, that Aaron assume Moishe dead and forgotten. "Better he thinks his brother dead and gone, then know he lives but cannot be near. He will soon forget his baby brother whom he knew for such a little time" they might have rationalized. But, Aaron had found out the secret that was his inheritance and was consequently initiated into the family secret with an unexpressed vow of ignorance and silence. Mitzrayim could not know or it would crush Moishe's--and Aaron's--people.
Eventually, Moishe found out about his heritage and people. While traveling through the land, he saw an Egyptian beating an Israelite and he killed the Egyptian in a fit of rage. He had made a choice that could not easily be undone. He had sided himself with the poor and oppressed even though so very few of them knew him. He fled into the desert where he would encounter God. Aaron would remain in the clutches of Mitzrayim with their people and continue to encounter the God that Moishe found only in the wilderness.
When Moishe returned, Aaron met him along the way and revealed his identity more clearly. As Moishe tried to rally the people of Israel around God's calling, Aaron stood in the gap between the people and the agent of their deliverance. Aaron became a bridge between the deliverer they never knew and the people so crushed and beaten by Mitzrayim. Aaron's trust in Moishe allowed the people to learn to trust this wandering leader.Further, Moishe insisted that Aaron was to be his "navi" or mouthpiece. Moishe wasn't known for his eloquence and, perhaps, had a stutter but God had chosen him. God had called Aaron to stand in the gap between Moishe and the world and be the prophet and mouthpiece for Moishe. Aaron lived into this calling.
Aaron stood in the gap between the people and Moishe. Further, he stood in the gap between a people with a vague yearning for a loving God and the loving God who reached out desperately for a people that could not and would not see God. In this way, the consecration of Aaron as a priest was a formal recognition of the calling that Aaron was already living out. He had stood before the people and pointed to God and God's movement all the while interceding for the people before the God they simultaneously sought and rejected.
Aaron's life and faith were far from perfect--he and Moishe did not always get along, his sons lose their lives by making the sacred profane, and he later built a golden calf for the people when they became fearful--but he must be remembered for standing in the gap for the people when Moishe was being called into the desert. Often, we focus on the great leadership of Moishe but it could not have been easy for Aaron to stay behind in the grip of Mitzrayim while his brother seemed to be able to escape it. Aaron did not leave his people and reminds us that God is not present solely in the wild and wonderful places but also in the places of death and oppression. Aaron--a High Priest of the Israelites--was committed to both his God and his people and held onto both even as they struggled with each other.
Aaron died many years later and his son took the role of High Priest. In his office and calling, he had served his God, his people, and his brother well and faithfully. His death was mourned for thirty day by all those who had depended upon him.