According to the oath There is no word in the Greek original for the preposition according to: but it is a common and well understood principle of language, that when the accusative case is put absolutely, there is a preposition to be understood, by which it is governed. The oath is mentioned, for the purpose of expressing more fully the firmness and sacredness of his truth: for such is his gracious condescension, that he deigns to employ his name for the support of our weakness. If his bare promises do not satisfy us, let us at least remember this confirmation of them; and if it does not remove all doubt, we are chargeable with heinous ingratitude to God, and insult to his holy name. To give to us Zacharias does not enumerate the several points of God's covenant, but shows that God's purpose, in dealing so kindly and mercifully with his people, was to redeem them.

The oath - This oath is recorded in Genesis 22:16-17. It was an oath in which God swore by himself (because he could swear by no greater, Hebrews 6:13-14) that he would surely bless Abraham and his posterity. That promise was now to be entirely fulfilled by the coming of the Messiah.

The oath which he swore to our father Abraham. When he swore by himself, because he could swear by no greater, that in blessing he would bless him; that his seed should possess the gates of his enemies, and in it all the nations of the earth should be blessed: all which have been fulfilled in Jesus the Messiah; see Genesis 22:16.

the oath . . . to . . . Abraham--The whole work and kingdom of Messiah is represented as a mercy pledged on oath to Abraham and his seed, to be realized at an appointed period; and at length, in "the fulness of the time," gloriously made good. Hence, not only "grace," or the thing promised; but "truth," or fidelity to the promise, are said to "come by Jesus Christ" (John 1:17).