Exodus 40:15

15 Anoint them, just as you anointed their father, to serve me as priests. Their anointing will bring them into a perpetual priesthood, down through the generations."

Exodus 40:15 Meaning and Commentary

Exodus 40:15

And thou shall anoint them as thou didst anoint their
father
For Aaron was first anointed, and then his sons:

that they may minister unto me in the priest's office;
which they might not do before their anointing, though separated for it, and called unto it:

for their anointing shall surely be an everlasting priesthood
throughout their generations;
that is, this ceremony of anointing was to be used in all ages at the investiture of the high priest with his office, until the Messiah should come, who would put an end to the Aaronic priesthood; for not common priests, only the successors of the high priest, were anointed in later times; this present unction serving for all the priests that should follow in successive generations, so long as the priesthood continued.

Exodus 40:15 In-Context

13 Dress Aaron in the sacred vestments. Anoint him. Consecrate him to serve me as priest.
14 Bring his sons and put tunics on them.
15 Anoint them, just as you anointed their father, to serve me as priests. Their anointing will bring them into a perpetual priesthood, down through the generations."
16 Moses did everything God commanded. He did it all.
17 On the first day of the first month of the second year, The Dwelling was set up.