16 You will recognize them by their fruit. Grapes are not gathered from thorns or figs from thistles, are they? 17 In the same way, every good tree bears good fruit, but the bad tree bears bad fruit. 18 A good tree is not able to bear bad fruit, nor a bad tree to bear good fruit. 19 Every tree that does not bear good fruit is cut down and thrown into the fire. 20 So then, you will recognize them by their fruit.

But, O my son, refuse thus thoughtlessly to identify these two things in the irrational and foolish fashion common to the mass of men, and ascribe no such confusion to the God of goodness. For these men refer the beginning and the end and the paternity of these ills to God Himself —whose end is near a curse. For they do not believe the word spoken by our Saviour and Lord Jesus Christ Himself in the Gospels, namely, that a good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. And how they can be bold enough to call God the maker and contriver of Satan and his wicked deeds, is a matter of great amazement to me.