John Gill - Exposition
John Gill
And he that shall swear by heaven,.... As the Jews were wont to do in common, but did not look upon such an oath as obligatory on them; [See comments on Matthew 5:34], though such an one sweareth by the throne of God; for heaven is God's throne, where he sits, and, in an eminent manner, displays the glory of his majesty: and by him that sitteth thereon, by God himself. Thus swearing by anything...