Matthew 13:25

(Quaest. in Matt. q. 11.) He says, While men slept, for while the heads of the Church were abiding in supineness, and after the Apostles had received the sleep of death, then came the Devil and sowed upon the rest those whom the Lord in His interpretation calls evil children. But we do well to enquire whether by such are meant heretics, or Catholics who lead evil lives. That He says, that they were sown among the wheat, seems to point out that they were all of one communion. But forasmuch as He interprets the field to mean not the Church, but the world, we may well understand it of the heretics, who in this world are mingled with the good; for they who live amiss in the same faith may better be taken of the chaff than of the tares, for the chaff has a stem and a root in common with the grain. While schismatics again may more fitly be likened to ears that have rotted, or to straws that are broken, crushed down, and cast forth of the field. Indeed it is not necessary that every heretic or schismatic should be corporally severed from the Church; for the Church bears many who do not so publicly defend their false opinions as to attract the attention of the multitude, which when they do, then are they expelled. When then the Devil had sowed upon the true Church divers evil errors and false opinions; that is to say, where Christ's name had gone before, there he scattered errors, himself was the rather hidden and unknown; for He says, And went his way. Though indeed in this parable, as we learn from His own interpretation, the Lord may be understood to have signified under the name of tares all stumbling-blocks and such as work iniquity.

But while people are asleep they do not act according to the command of Jesus, "Watch and pray that you enter not into temptation." At that point the devil on the watch sows what are called tares—that is, evil opinions—over and among the good seeds that are from the Word. According to this the whole world might be called a field, and not the church of God only. For the Son of Man sowed the good seed throughout the entire world, but the wicked one sowed tares—that is, evil words—which, springing from wickedness, are children of the evil one.

So that you need not be afraid to ascribe to him the mastery and dominion over that second, later, and deteriorated nature (of which we have been speaking), when you read of him as "the sewer of tares, and the nocturnal spoiler of the crop of corn.

Understand that the men who are asleep are the leaders of the Churches. Do not welcome servants of the household of the father except for the angels, who daily see the Father's face (Matt. XVIII). But the devil is called the enemy of man because he stopped being God. And it is written of him in the ninth psalm: Arise, O Lord, let not man prevail (Psalm IX, 20). Therefore, let the one who is placed over the Church not sleep, lest through his negligence the enemy sows weeds, that is, the dogmas of heretics.

What is the difference between this, and the parable before it? There He speaks of them that have not at all holden with Him, but have started aside, and have thrown away the seed; but here He means the societies of the heretics. For in order that not even this might disturb His disciples, He foretells it also, after having taught them why He speaks in parables. The former parable then means their not receiving Him; this, their receiving corrupters. For indeed this also is a part of the devil's craft, by the side of the truth always to bring in error, painting thereon many resemblances, so as easily to cheat the deceivable. Therefore He calls it not any other seed, but tares; which in appearance are somewhat like wheat. Then He mentions also the manner of his device. For "while men slept," saith He. It is no small danger, which He hereby suspends over our rulers, to whom especially is entrusted the keeping of the field; and not the rulers only, but the subjects too. And He signifies also that the error comes after the truth, which the actual event testifies. For so after the prophets, were the false prophets; and after the apostles, the false apostles; and after Christ, Antichrist. For unless the devil see what to imitate, or against whom to plot, he neither attempts, nor knows how. Now then also, having seen that "one brought forth a hundred, another sixty, another thirty," he proceeds after that another way. That is, not having been able to carry away what had taken root, nor to choke, nor to scorch it up, he conspires against it by another craft, privily casting in his own inventions. And what difference is there, one may say, between them that sleep, and them that resemble the wayside? […]