Therefore you and your sons with you shall keep your priests' office for everything of the altar and inside the veil. And you shall serve. I have given your priest's office as a service of gift. And the stranger that comes near shall be put to death.
(for those priests were made without an oath, but this one was made with an oath by Him who said to Him, "The Lord swore and will not repent, You are a priest forever after the order of Melchizedek,")