Heb Hebrews, chapter Epistle to the Hebrews, chapter 7
And inasmuch as [it is] not apart from oath (for those indeed apart from oath have become priests, and He [became priest] with an oath through Him who is saying to Him, “The LORD swore, and will not regret, You [are] a priest throughout the age, according to the order of Melchizedek”), Psa 110:4