Matthew Poole and continuators on Luke 1:72

72 To perform the mercy promised to our fathers, and to remember his holy covenant.

This was that which God had told them by his Prophets, that a mighty Salvation, should arise to them out of the house of David, by which they should be saved from their Enemies. By which Enemies the generality of the Jews understood their temporal Enemies, made of Flesh, and Blood. But Zachariah speaking by the Spirit of Prophecy, must needs have a truer Notion of it, as it signifies our spiritual Enemies. All this is attributed to Gods Mercy, and faithfulness, his Mercy freely looking upon his Creatures in Distress, and Misery, his faithfulness in remembrance of his holy Covenant, made to Adam, Abraham, David, &c. but it is more particularly explained.