Now that is in our power, of which equally with its opposite we are masters,--as, say, to philosophize or not, to believe or disbelieve. In consequence, then, of our being equally masters of each of the opposites, what depends on us is found possible. Now the commandments may be done or not done by us, who, as is reasonable, are liable to praise and blame. And those, again, who are punished on account of sins committed by them, are punished for them alone; for what is done is past, and what is done can never be undone. The sins committed before faith are accordingly forgiven by the Lord, not that they may be undone, but as if they had not been done. “But not all,” says Basilides, “but only sins involuntary and in ignorance, are forgiven;” as would be the case were it a man, and not God, that conferred such a boon. To such an one Scripture says, “Thou thoughtest that I would be like thee.”[662] But if we are punished for voluntary sins, we are punished not that the sins which are done may be undone, but because they were done. But punishment does not avail to him who has sinned, to undo his sin, but that he may sin no more, and that no one else fall into the like. Therefore the good God corrects for these three causes: First, that he who is corrected may become better than his former self; then that those who are capable of being saved by examples may be driven back, being admonished; and thirdly, that he who is injured may not be readily despised, and be apt to receive injury. And there are two methods of correction--the instructive and the punitive, which we have called the disciplinary. It ought to be known, then, that those who fall into sin after baptism[663] are those who are subjected to discipline; for the deeds done before are remitted, and those done after are purged. It is in reference to the unbelieving that it is said, “that they are reckoned as the chaff which the wind drives from the face of the earth, and the drop which falls from a vessel.”[664] CHAPTER XXV. TRUE PERFECTION CONSISTS IN THE KNOWLEDGE AND LOVE OF GOD.