13 For when God made a promise to Abraham, because He could swear by no one greater, He swore by Himself,
because [since] He could swear by no one greater,
The word “because” gives the reason God swore by Himself. There was no one greater to whom He could appeal. Unlike a human being, God is unable to appeal to a greater authority than Himself to guarantee a promise.
He swore by Himself,
God swearing an oath by Himself makes His covenant unconditional. There is no condition other than God’s promise that is at stake. Whether people respond to His promise or not is immaterial. God is bound to His Word, by His character. His oath guarantees the validity of His promise. It removes any doubt.
It is odd that God would employ an oath, as this is something to which men have to resort. Humans do this because of skepticism about the unreliability of other people’s claims. It is easy for people to make promises and not keep them. However, God made an oath because of the perversity of the human situation. He condescended to human frailty by doing this. It was not a matter of His credibility but their credibility that was at stake.
If God had sworn by something or someone other than Himself, it would have implied that the something or someone was greater than Himself. He could be no less than God in what He did. His Word must be absolutely certain. Human words have elements of uncertainty in them. God’s appeal was to the infallible integrity of an absolute God. God alone was responsible for His promise. He did this because there was no one outside of Himself who was greater than He was.
The certainty of God’s faithfulness is the ground of our hope.
God made a pledge to give the believer hope and assurance. God’s promises are very important during a crisis. The church of the book of Hebrews underwent fierce hostility against them (He 10:32–34). They were becoming “slothful” about their faith (He 6:12). They did not have the kind of endurance Christ had (He 12:1-2). God’s promises are of great importance in times like this for Christians today. His promises will sustain us, but they must be believed and applied to one’s life.