Exodus 40:15
"And thou shalt anoint them, as thou didst anoint their father, that they may minister unto me in the priest’s office: for their anointing shall surely be an everlasting priesthood throughout their generations."
Cross References (ranked by relevance)
And he shall have it, and his seed after him, even the covenant of an everlasting priesthood; because he was zealous for his God, and made an atonement for the children of Israel.
The LORD hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek.
And thou shalt speak unto the children of Israel, saying, This shall be an holy anointing oil unto me throughout your generations.
And without all contradiction the less is blessed of the better.
And this day shall be unto you for a memorial; and ye shall keep it a feast to the LORD throughout your generations; ye shall keep it a feast by an ordinance for ever.
Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually.
And thou shalt gird them with girdles, Aaron and his sons, and put the bonnets on them: and the priest’s office shall be theirs for a perpetual statute: and thou shalt consecrate Aaron and his sons.
Whosoever compoundeth any like it, or whosoever putteth any of it upon a stranger, shall even be cut off from his people.