For when God made a promise to Abraham, because he could swear by no greater, he swore by himself,
All Commentaries on Hebrews 6:13 Go To Hebrews 6
John Chrysostom
AD 407
Having boldly reflected on the faults of the Hebrews, and sufficiently alarmed them, he consoles them, first, by praises, and secondly (which also is the stronger ground), by the [thought] that they would certainly attain the object of their hope. Moreover he draws his consolation, not from things future, but again from the past, which indeed would the rather persuade them. For as in the case of punishment, he alarms them rather by those [viz. things future], so also in the case of the prizes [set before them], he encourages them by these [viz. by things past], showing [herein] God's way of dealing. And that is, not to bring in what has been promised immediately, but after a long time. And this He does, both to present the greatest proof of His power, and also to lead us to Faith, that they who are living in tribulation without having received the promises, or the rewards, may not faint under their troubles.
And omitting all [the rest], though he had many whom he might have mentioned, he brought forward Abraham both on account of the dignity of his person, and because this had occurred in a special way in his case.
