Charles Ellicott Commentary Hebrews 6:17

"Wherein God, being minded to show more abundantly unto the heirs of the promise the immutability of his counsel, interposed with an oath;" — Hebrews 6:17 (ASV)

Wherein.—Since this is the case.

Of promise.—Rather, of the promise. The promise made to Abraham was substantially and really that which embraced all Messianic hope. Of this promise, not only Abraham’s sons but all they which are of faith (Galatians 3:7; Galatians 3:29), Abraham’s spiritual seed, are the heirs. In an Epistle so distinctly Pauline, there can be no doubt as to this interpretation.

Confirmed it by an oath.—Literally, mediated with an oath. When a man confirms a promise or declaration to another by solemn appeal to God, between the two God is Mediator. Condescending to man’s weakness, that the certainty may be more abundant, God thus confirms His word, at once the Promiser and the Mediator: God the Promiser (if we may so speak) appeals to God the Hearer and Witness of the oath.

We cannot doubt, as we read this whole passage, that there is a special reason for the emphasis thus laid on God’s oath to Abraham. The writer dwells on this confirmation of the divine word of promise, not merely because it is the first recorded in sacred history, but because he has in mind the declaration of Psalm 110:4. He does not yet refer to this, though he has quoted from the verse repeatedly without mentioning the divine oath. But throughout the section before us, he is preparing the way for his later argument in Hebrews 7:21.