And none of this happened without an oath. For others became priests without an oath, but Jesus became a priest with an oath by the One who said to Him: "The Lord has sworn and will not change His mind: 'You are a priest forever.'" Because of this oath, Jesus has become the guarantee of a better covenant.
The LORD has sworn and will not change His mind: "You are a priest forever in the order of Melchizedek."
Walk the Square · a single-voice walk of this pair around the Clowney square8:04
Significance
Hebrews quotes Psalm 110:4's divine oath ("The LORD has sworn and will not change His mind: 'You are a priest forever'") to demonstrate Christ's superiority over the Levitical priesthood. The key argument is that Levitical priests were appointed "without an oath" (χωρὶς ὁρκωμοσίας, Heb 7:20), whereas Jesus became a priest "with an oath" (μετὰ ὁρκωμοσίας, Heb 7:21). This oath makes Jesus "the guarantee of a better covenant" (ἔγγυος, Heb 7:22). The author's logic: oath-confirmed priesthood > non-oath-confirmed priesthood; therefore, Melchizedekian priesthood > Levitical priesthood. The immutability of God's oath (echoing Heb 6:17-18's exposition of the Abrahamic oath) secures the permanence of Christ's priestly ministry and, consequently, the salvation of all who come to God through Him (Heb 7:25).