John Chrysostom

Which mercy we find not indeed by our own seeking, but God from on high hath appeared to us, as it follows; Whereby (i. e. by His tender mercy) the dayspring from on high (that is, Christ) hath visited us, taking upon Him our flesh.

Catena Aurea by Aquinas ↗

Cyril of Alexandria

For those under the law, and dwelling in Judea, the Baptist was, as it were, a lamp, preceding Christ: and God so spake before of him; "I have prepared a lamp for My Christ." And the law also typified him in the lamp, which in the first tabernacle it commanded should be ever kept alight. But the Jews, after being for a short time pleased with him, flocking to his baptism, and admiring his mode of life, quickly made him sleep in death, doing their best to quench the ever-burning lamp. …

Commentary On Luke, Fragments On Luke 1 ↗

Theophylact of Ohrid

And He forgave us our sins out of the tender mercy of His compassion, and not for our works; for we had done nothing good, yet He, who is called the Dawn, looked upon us from on high. For He is the Sun of righteousness and shone upon us who were in darkness, that is, in sin. Two evils held sway over human nature: ignorance of God, in which the pagans found themselves, and sin, which the Jews possessed, even though they knew God.

Commentary on Luke ↗

Bede

When Zechariah says, "for his people," he certainly does not mean that he found them his people upon his arrival but that he made them his by visiting and redeeming them. Do you want to hear about the condition in which he found this people and what he made of them? …

Homilies on the Gospels 2.20 ↗

Bonaventure

He commends also John's proclamation from the proximity of the divine presence, when he says: Through the bowels of mercy of our God. And he describes this in three ways: first, as visiting to console the affection; second, as illuminating to teach the intellect, at: To illuminate those, etc.; third, as directing to rectify the action, at: To direct the feet, etc. …

Commentary on Luke, Chapter 1 ↗