Ambrose of Milan — as excerpted in the Catena Aurea on Luke 3:7-9

“We see these men through the compassion of God, inspired with prudence to seek repentance of their crimes, dreading with wise devotion the terror of the judgment to come. Or perhaps, according to the precept, Be ye wise as serpents, (Matt. 10:16.) they are shewn to have a natural prudence, who perceive what is coming, and earnestly desire help, though they still forsake not what is hurtful.”