David gave Solomon directions for the groups of the priests and Levites. David told him about all the work of serving in the Temple of the Lord and about the items to be used in the Temple service
The Levites and all the people of Judah obeyed everything Jehoiada the priest had commanded. He did not excuse anyone from the groups of the priests. So each commander took his men who came on duty on the Sabbath with those who went off duty on the Sabbath.
King Hezekiah appointed groups of priests and Levites for their special duties. They were to offer burnt offerings and fellowship offerings, to worship, and to give thanks and praise at the gates of the Lord’s house.
Solomon followed his father David’s instructions and chose the groups of priests for their service and the Levites to lead the praise and to help the priests do their daily work. And he chose the gatekeepers by their groups to serve at each gate, as David, the man of God, had commanded.
Then they put the priests and the Levites into their separate groups. Each group had a certain time to serve God in the Temple at Jerusalem as it is written in the Book of Moses.
“Tell your brother Aaron to come to you, along with his sons Nadab, Abihu, Eleazar, and Ithamar. Separate them from the other Israelites to serve me as priests.
But Nadab and Abihu died in the presence of the Lord when they offered the wrong kind of fire before the Lord in the Desert of Sinai. They had no sons. So Eleazar and Ithamar served as priests during the lifetime of their father Aaron.