21 And that no lie is of the truth. He concedes to them a judgment, by which they could distinguish truth from falsehood; for it is not the dialectic proposition, that falsehood differs from truth, (such as are taught as general rules in the schools;) but what is said is applied to that which is practical and useful; as though he had said, that they did not only hold what was true, but were also so fortified against the impostures and fallacies of the ungodly, that they wisely took heed to themselves. Besides, he speaks not of this or of that kind of falsehood; but he says, that whatever deception Satan might contrive, or in whatever way he might attack them, they would be able readily to distinguish between light and darkness, because they had the Spirit as their guide.