Hebrews 7:21-24

(for they have become priests without an oath, but He with an oath by Him who said to Him: “The LORD has sworn And will not relent, ‘You are a priest forever According to the order of Melchizedek’ ”), by so much more Jesus has become a surety of a better covenant. Also there were many priests, because they were prevented by death from continuing. But He, because He continues forever, has an unchangeable priesthood.