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 Gill 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 that has any relation to God, is implicitly swearing by him; and therefore ought to be considered as binding, as if he was expressed in it; since an appeal cannot be made to things inanimate, nor indeed to any creature, but to God, the searcher of hearts.