Ex 28:1

28:1 serve me as priests. First and foremost, the priests were to serve as mediators between God and man. As priests and representatives of a holy God, Aaron and his sons participated in the holiness of the tabernacle and were held to strict standards of ritual purity (Lev. 21:1–22:16). In addition to their ceremonial duties, such as offering sacrifices and caring for the place of worship, they acted as judges (Deut. 17:8–13), dispensed blessings (Num. 6:22–27), gave oracles (Num. 27:21), and taught God’s law to the people (Deut. 33:10).

Nadab and Abihu. These two sons of Aaron were killed for unlawful activity (Lev. 10:1–2). Aaron was succeeded by Eleazar (Deut. 10:6).