Matthew 13:29

The workers of the householder wanted to go and gather up the weeds, but they were not allowed to do so. Though they indeed wanted to gather them up, they were not allowed to separate the weeds. They did what they were suited for and left it to the angels to do the separation. At first they were unwilling to leave the separation of the weeds up to the angels. But the householder, who knew them all and saw that a separation was necessary, ordered them to put up with the weeds and not to separate them. In answer to their words, "Do you want us to go and gather them up?" he replied, "No, lest in gathering the weeds you root up the wheat along with them." "Therefore, Lord, will the weeds also be with us in the barn?" "At harvest time I will say to the reapers, 'Gather up first the weeds, and bind them in bundles to burn. Allow what you do not have with you in the barn to grow in the field.' "

(Quaest. in Matt. q. 12.) Wherein He renders them more patient and tranquil. For this He says, because good men while yet weak, have need in some things of being mixed up with bad, either that they may be proved by their means, or that by comparison with them they may be greatly stimulated and drawn to a better course. Or perhaps the wheat is declared to be rooted up if the tares should be gathered out of it, on account of many who though at first tares would, after become wheat; yet they would never attain to this commendable change were they not patiently endured while they were evil. Thus were they rooted up, that wheat which they would become in time if spared, would be rooted up in them. It is then therefore He forbids that such should be taken away out of this life, lest in the endeavour to destroy the wicked, those of them should be destroyed among the rest who would turn out good; and lest also that benefit should be lost to the good which would accrue to them even against their will from mixing with the wicked. But this may be done seasonably when, in the end of all, there remains no more time for a change of life, or of advancing to the truth by taking opportunity and comparison of others' faults; therefore He adds, Let both grow together until the harvest, that is, until the judgment. (Cont. Ep. Parm. iii. 2.) For when any one of the number of Christians included in the Church is found in such sin as to incur an anathema, this is done, where danger of schism is not apprehended, with tenderness, not for his rooting out, but for his correction. […]

For room for repentance is left, and we are warned that we should not hastily cut off a brother, since one who is to-day corrupted with an erroneous dogma, may grow wiser tomorrow, and begin to defend the truth; wherefore it is added, Lest in gathering together the tares ye root out the wheat also.

But this seems to contradict that command, Put away the evil from among you. (1 Cor. 5:13) For if the rooting up be forbidden, and we are to abide in patience till the harvest-time, how are we to cast forth any from among us? But between wheat and tares (which in Latin we call 'lolium') so long as it is only in blade, before the stalk has put forth an ear, there is very great resemblance, and none or little difference to distinguish them by. The Lord then warns us not to pass a hasty sentence on an ambiguous word, but to reserve it for His judgment, that when the day of judgment shall come, He may cast forth from the assembly of the saints no longer on suspicion but on manifest guilt.

What then doth the Master? He forbids them, saying, "Lest haply ye root up the wheat with them." And this He said, to hinder wars from arising, and blood and slaughter. For it is not right to put a heretic to death, since an implacable war would be brought into the world. By these two reasons then He restrains them; one, that the wheat be not hurt; another, that punishment will surely overtake them, if incurably diseased. Wherefore, if thou wouldest have them punished, yet without harm to the wheat, I bid thee wait for the proper season. But what means, "Lest ye root up the wheat with them?" Either He means this, If ye are to take up arms, and to kill the heretics, many of the saints also must needs be overthrown with them; or that of the very tares it is likely that many may change and become wheat. If therefore ye root them up beforehand, ye injure that which is to become wheat, slaying some, in whom there is yet room for change and improvement. He doth not therefore forbid our checking heretics, and stopping their mouths, and taking away their freedom of speech, and breaking up their assemblies and confederacies, but our killing and slaying them. But mark thou His gentleness, how He not only gives sentence and forbids, but sets down reasons.