3. Further, we know from other sources the faith itself which a man sees to be in his own heart, if he believes, or not to be there, if he does not believe: but not as we know bodies, which we see with the bodily eyes, and think of even when absent through the images of themselves which we retain in memory; nor yet as those things which we have not seen, and which we frame howsoever we can in thought from those which we have seen, and commit them to memory, that we may recur to them when we will, in order that therein we may similarly by recollection discern them, or rather discern the images of them, of what sort soever these are which we have fixed there; nor again as a living man, whose soul we do not indeed see, but conjecture from our own, and from corporeal motions gaze also in thought upon the living man, as we have learnt him by sight. Faith as not so seen in the heart in which it is, by him whose it is; but most certain knowledge holds it fast, and conscience proclaims it. Although therefore we are bidden to believe on this account, because we cannot see what we are bidden to believe; nevertheless we see faith itself in ourselves, when that faith is in us; because faith even in absent things is present, and faith in things which are without us is within, and faith in things which are not seen is itself seen, and itself none the less comes into the hearts of men in time; and if any cease to be faithful and become unbelievers, then it perishes from them. And sometimes faith is accommodated even to falsehoods; for we sometimes so speak as to say, I put faith in him, and he deceived me. And this kind of faith, if indeed it too is to be called faith, perishes from the heart without blame, when truth is found and expels it. But faith in things that are true, passes, as one should wish it to pass, into the things themselves. For we must not say that faith perishes, when those things which were believed are seen. For is it indeed still to be called faith, when faith, according to the definition in the Epistle to the Hebrews, is the evidence of things not seen?