Theodore: It is needful that one must either, as the Apostle says, “be renewed in the spirit of the mind,” 1427 and daily advance by “pressing forward to those things which are before,” 1428 or, if one neglects to do this, the sure result will be to go back, and become p. 360 worse and worse. And therefore the mind cannot possibly remain in one and the same state. Just as when a man, by pulling hard, is trying to force a boat against the stream of a strong current he must either stem the rush of the torrent by the force of his arms, and so mount to what is higher up, or letting his hands slacken be whirled headlong down stream. Wherefore it will be a clear proof of our failure if we find that we have gained nothing more, nor should we doubt but that we have altogether gone back, whenever we find that we have not advanced upwards, because, as I said, the mind of man cannot possibly continue in the same condition, nor so long as he is in the flesh will any of the saints ever reach the height of all virtues, so that they continue unalterable. For something must either be added to them or taken away from them, and in no creature can there be such perfection, as not to be subject to the feeling of change; as we read in the book of Job: “What is man that he should be without spot, and he that is born of a woman that he should appear just? Behold among His saints none is unchangeable, and the heavens are not pure in His sight.” 1429 For we confess that God only is unchangeable, who alone is thus addressed by the prayer of the holy prophet “But Thou art the same,” 1430 and who says of Himself “I am God, and I change not,” 1431 because He alone is by nature always good, always full and perfect, and one to whom nothing can ever be added, or from whom nothing can be taken away. And so we ought always with incessant care and anxiety to give ourselves up to the acquirement of virtue, and constantly to occupy ourselves with the practice of it, lest, if we cease to go forward, the result should immediately be a going back. For, as we said, the mind cannot continue in one and the same condition, I mean without receiving addition to or diminution of its good qualities. For to fail to gain new ones, is to lose them, because when the desire of making progress ceases, there the danger of going back is present.