the oath that he swore to our father Abraham, to grant us
73. 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.
We have here the song wherewith Zacharias praised God when his mouth was opened; in it he is said to prophesy (Luk 1:67), and so he did in the strictest sense of prophesying; for he foretold things to come concerning the kingdom of the Messiah, to which all the prophets bear witness. Observe, I.
Commenting on Luke 1:67-80
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 Gen 22:16. .