Chapter XXIV. 78. Here, therefore, those who promise a wisdom and a knowledge of the truth which they do not possess, are especially to be guarded against; as, for instance, heretics, who fre- quently commend themselves on account of their fewness. And hence, when He had said that there are few who find the strait gate and the narrow way, lest they [the heretics] should falsely substitute themselves under the pretext of their fewness, He immediately added, “Beware of false prophets,462 which come to you in sheep’s clothing, but inwardly they are ravening wolves.” But such parties do not deceive the single eye, which knows how to dis- tinguish a tree by its fruits. For He says: “Ye shall know them by their fruits.” Then He adds the similitudes: “Do men gather grapes of thorns, or figs of thistles? Even so, every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that brin- geth not forth good fruit463 is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them.” 79. And in [the interpretation of] this passage we must be very much on our guard against the error of those who judge from these same two trees that there are two original natures, the one of which belongs to God, but the other neither belongs to God nor springs from Him. And this error has both been already discussed in other books [of ours]464 very copiously, and if that is still too little, will be discussed again; but at present we have merely to show that the two trees before us do not help them. In the first place, because it is so clear that He is speaking of men, that whoever reads what goes before and what follows will wonder at their blindness. Secondly, they fix their attention on what is said, “A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit,” and therefore think that neither can it happen that an evil soul should be changed into something better, nor a good one into something worse; as if it were said, A good tree cannot become evil, nor an evil tree good. But it is said, “A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.” For the tree is certainly the soul itself, i.e. the man himself, but the fruits are the works of the man; an evil man, therefore, cannot perform good works, nor a good man evil works. If an evil man, therefore, wishes to perform good works, let him first become good. So the Lord Himself says in another passage more plainly: “Either make the tree good, or make the tree bad.” But if He were figuratively representing the two natures of such parties by these two trees, He would not say, “Make:” for who of 462 Cavete a pseudoprophetis; Vulgate, attendite a falsis prophetis. 463 Excellency of fruitage is sanctity of life (Bonitas fructuum est sanctitas vitæ (Bengel). 464 More particularly his works against the Manichæans, Contra Faustum Manichæum, etc. Augustin also made much use of this passage against the Pelagians, to show that the will must be aided to produce good thoughts and deeds; that the unregenerate man is incapable of restoring himself. Chapter XXIV 146 Chapter XXIV