Church Fathers Commentary Luke 1:72-74

"To show mercy towards, our fathers, And to remember his holy covenant; The oath which he spake unto Abraham our father, To grant unto us that we being delivered out of the hand of our enemies Should serve him without fear," — Luke 1:72-74 (ASV)

The Venerable Bede: Having announced that the Lord would be born from the house of David, according to the prophet's declaration, he now says that this same Lord will deliver us to fulfill the covenant He made with Abraham. This is because the gathering of the Gentiles, or the incarnation of Christ, was promised chiefly to these patriarchs of Abraham's lineage. But David is mentioned first because the holy assembly of the Church was promised to Abraham, whereas it was told to David that Christ was to be born from him. Therefore, after speaking of David, he adds the words concerning Abraham: To perform the mercy promised to our fathers...

Origen of Alexandria: I believe that at the coming of our Lord and Savior Jesus Christ, Abraham, Isaac, and Jacob all partook of His mercy. For we should not believe that those who had previously seen His day and were glad would later derive no benefit from His coming, since it is written, Having made peace through the blood of his Cross, whether in earth or in heaven (Colossians 1:20).

Theophylact of Ohrid: The grace of Christ extends even to those who are dead, because through Him we will rise again—not only us, but also those who died before us. He also showed His mercy to our forefathers by fulfilling all their hopes and desires. This is why it says, And to remember his holy covenant—that is, the covenant in which He said, Blessing, I will bless you, and multiplying, I will multiply you (Genesis 22:17). For Abraham was multiplied in all nations, which became his children by adoption by following the example of his faith.

Moreover, the fathers, seeing their children enjoy these blessings, rejoice with them as if they had received this mercy themselves. This leads to the next phrase: The oath which he swore to our father Abraham, that he would grant to us (Luke 1:73).

St. Basil the Great: But let no one, upon hearing that the Lord had sworn to Abraham, be tempted to swear. For just as the "wrath of God" does not signify an emotional passion but rather a just punishment, so also God does not swear as a man does. Instead, His word is given to us with the full force of an oath, confirming what He promised with an unchangeable decree.