Gregory the Great
Catena Aurea · Lukasevangelium 3
Then said he to the multitude that came forth to be baptized of him, O generation of vipers, who hath warned you to flee from the wrath to come? Bring forth therefore fruits worthy of repentance, and begin not to say within yourselves, We have Abraham to our father: for I say unto you, That God is able of these stones to raise up children unto Abraham. And now also the axe is laid unto the root of the trees: every tree therefore which bringeth not forth good fruit is hewn down, and cast into the fire,
(ubi sup.) But the Jews glorying in their noble birth were unwilling to acknowledge themselves sinners, because they were descended from the stock of Abraham. So then it is rightly said, And begin not to say within yourselves, we have Abraham for our father.