The Sons of Aaron
3This is the lineage of Aaron and Moses at the time when the Lord spoke with Moses on Mount Sinai. 2These are the names of the sons of Aaron: Nadab the firstborn, and Abihu, Eleazar, and Ithamar; 3these are the names of the sons of Aaron, the anointed priests, whom he ordained to minister as priests. 4Nadab and Abihu died before the Lord when they offered unholy fire before the Lord in the wilderness of Sinai, and they had no children. Eleazar and Ithamar served as priests in the lifetime of their father Aaron.
The Duties of the Levites
5 Then the Lord spoke to Moses, saying: 6Bring the tribe of Levi near, and set them before Aaron the priest, so that they may assist him. 7They shall perform duties for him and for the whole congregation in front of the tent of meeting, doing service at the tabernacle; 8they shall be in charge of all the furnishings of the tent of meeting, and attend to the duties for the Israelites as they do service at the tabernacle. 9You shall give the Levites to Aaron and his descendants; they are unreservedly given to him from among the Israelites. 10But you shall make a register of Aaron and his descendants; it is they who shall attend to the priesthood, and any outsider who comes near shall be put to death.
11 Then the Lord spoke to Moses, saying: 12I hereby accept the Levites from among the Israelites as substitutes for all the firstborn that open the womb among the Israelites. The Levites shall be mine, 13for all the firstborn are mine; when I killed all the firstborn in the land of Egypt, I consecrated for my own all the firstborn in Israel, both human and animal; they shall be mine. I am the Lord. -- Numbers 3:1-13
I remember looking at my newborn son and wondering how he was going to turn out. I made lots of mistakes raising him, but he still turned out to be a fine, hard-working man with a good job, a wife and a life that seems to work for him. I bet Aaron did the same thing when each of his sons was born, only he probably knew they would follow him into what amounted to the family business of being God's priests.
For much of human history, it has been a given that a son would follow his father into the same trade or business. Jesus was the son of a tekton, what we would call a carpenter but who actually was involved in the building trade, so he was expected to follow that profession (what a surprise for his family when he struck out for an entirely different job!). Aaron was a priest and so it was expected that his sons would also be priests -- which they were. Aaron's first two sons died childless, a terrible thing in those days. Jewish interpretation of just why they died varies. Some say they were so holy God took them before they had children, else they would have had to stay on earth in order to provide for those children while others say they exceeded their orders from Moses and, in an excess of zeal, brought unauthorized fire and incense before the Lord for which God in turned burned them to pay for their sin of exuberance.
Aaron still had two sons, though, who did live, multiply, and serve as the priests, the kohanin, while his kinsmen, the tribe of Levi, were called to defend the tabernacle, care for it and its furnishings, and to assist the kohanin and people (Yisraelim) in their duties to God. God had originally planned for the firstborn son of each household to be dedicated to God's service as well as the firstborn animal to be for a sacrifice, but once the slaughter of the firstborn in Egypt took place, God accepted the Levites as representing the firstborn of each Jewish household. The name Cohen today often means a direct descent from Aaron.
Today we do not have a hereditary priesthood. That priesthood died with the destruction of the Second Temple in 70AD. Instead we raise people up from our various congregations and help them discern their call from God and to what level of service. We give them a course of study and, after a successful completion of that, we have them ordained by a bishop. Their duties are primarily sacramental which includes presiding at the Eucharist, performing baptisms and teaching, but they also are expected to be something like the CEO of a small company or corporation. The laity usually does things like care for the cleaning of the sanctuary if not the whole building, caring for the altar and its accouterments, arranging flowers, reading, ushering, teaching Sunday school and the like. We generally leave pastoral visits to the sick and shut-ns to the clergy.
Yet we are all priests by virtue of our baptisms. Look at our Baptismal Covenant which we renew every time there is a baptism during the worship service and at least twice a year if there are no baptisms at all. We agree, with God's help, to continue the teachings and fellowship including participation in the Eucharist and the prayers, to resist temptation and consciously repent of our sins, proclaim the word and example of Christ, to seek to serve Christ in all persons, and strive for justice and peace for all people. Our priesthood might not entitle us to consecrate the sacraments but there's not a lot else we can't do as priests, including teaching, sometimes preaching, serving at the altar in some capacity other than presider, and make visits to those who cannot otherwise come to church. In short, we are all the equivalent of the Levites, set apart by God to serve God and God's people, whether or not we are the firstborn or even the firstborn son. God has chosen us for this work and we promise to do it with every repetition of the Baptismal Covenant.
Jesus called people from several professions, tribal affiliations and villages to the service of God; he would teach them the things they would need to know and do. There was no need of a second priesthood as the Temple was still standing and used for the required sacrifices. The priesthood Jesus conferred on the disciples was as shepherds, teachers and witnesses, roles which he wanted them to pass on to their own disciples. We recognize it as the priesthood of all believers.
We don't all follow in the professions our fathers practiced, but in the case of Jesus, we are expected to follow in the path he showed us even if our normal work is as a lawyer, bookkeeper, teacher, sanitation worker, or any other profession, including that of parent. By God's own grace and the sacrifice of Jesus, we are called to practice our priesthood in the world. Jesus our kinsman and high priest has given us this duty and we are expected to accept it and actually do something with it.
We may not all be great, sometimes we will be very flawed vessels indeed, but we can do Kingdom work in whatever calling we have, whatever profession by which we earn our living, and by what passion we have that meets the world's needs. By keeping our eyes on the job our Father has set for us, we can serve out our priesthood in service to God and others, which is a pretty good thing.