“Worse yet, since good and evil in this world commonly inhabit not only the same field but even the same individual human beings – since, that is, there are no unqualified good guys any more than there are any unqualified bad guys — the only result of a truly dedicated campaign to get rid of evil will be the abolition of literally everybody.
Indeed, that puts the finger on the whole purpose of the enemy’s sowing of the weeds. He has no power against goodness in and of itself: the wheat is in the field, the kingdom is in the world, and there is not a thing he can do about any of it. Evil, like darnel, is a counterfeit of reality, not reality itself. It is a parasite on being, not being itself.
As the parable develops its point, though, the enemy turns out not to need anything more than negative power. He has to act only minimally on his own to wreak havoc in the world; mostly, he depends on the forces of goodness, insofar as he can sucker them into taking up arms against the confusion he has introduced, to do his work. That is precisely why the enemy goes away after sowing the weed: he has no need whatsoever to hang around. Unable to take positive action anyway – having no real power to much up the operation – he simply sprinkles around a generous helping of darkness and waits for the children of light to get flustered enough to do the job for him. Goodness itself, in other words, if it is sufficiently committed to plausible, right-handed strong arm methods, will in the very name of goodness do all and more than all that evil ever had in mind.
One word in passing. If you are worrying that this exposition might for the basis of a case for pacifism, you should continue to worry. But you should also make a distinction. The parable, it seems to me, does not say that resistance to evil is morally wrong, only that it is salvifically ineffective. You may, therefore, make out as many cases as you like for just wars, capital punishment, or any other sensible, right-handed solution to the presence of malefactors on earth; but you must not assume that such solutions will necessarily make the world a better place. You may, in short, take the sword, but you should also remember that those who do so inevitably perish by the sword – descriptively, not prescriptively. God does not punish people for being nonpacifists; war alone is punishment enough. But even though pacifism seems not to be enjoined by Scripture, we should note for the record that the parable of the weeds suggests that – pro tem at least – God himself is a pacifist. You don’t have to be one, therefore; but pro the only tem you have, you might find the company quite good.”
— Robert Fararr Capon, Kingdom Grace Judgment (87-88)