Catena Aurea on Luke 3:7–9: John Chrysostom

Now they say that the female viper kills the male in copulation, and the fœtus as it increases in the womb kills the mother, and so comes forth into life, bursting open the womb in revenge as it were of its father’s death; the viper progeny therefore are parricides. Such also were the Jews, who killed their spiritual fathers and teachers. But what if he found them not sinning, but beginning to be converted? He ought not surely to rebuke them, but to comfort them. We answer, that he gave not heed to those things which are outward, for he knew the secrets of their hearts, the Lord revealing them to him; for they vaunted themselves too much in their forefathers. Cutting therefore at this root, he calls them a generation of vipers, not indeed that he blamed the Patriarchs, or called them vipers.