It is for this reason, then, that the nature of the Trinity is called simple, because it has not anything which it can lose, and because it is not one thing and its contents another, as a cup and the liquor, or a body and its colour, or the air and the light or heat of it, or a mind and its wisdom. For none of these is what it has: the cup is not liquor, nor the body colour, nor the air light and heat, nor the mind wisdom. And hence they can be deprived of what they have, and can be turned or changed into other qualities and states, so that the cup may be emptied of the liquid of which it is full, the body be discoloured, the air darken, the mind grow silly. The incorruptible body which is promised to the saints in the resurrection cannot, indeed, lose its quality of incorruption, but the bodily substance and the quality of incorruption are not the same thing. For the quality of incorruption resides entire in each several part, not greater in one and less in another; for no part is more incorruptible than another. The body, indeed, is itself greater in whole than in part; and one part of it is larger, another smaller, yet is not the larger more incorruptible than the smaller. The body, then, which is not in each of its parts a whole body, is one thing; incorruptibility, which is throughout complete, is another thing;—for every part of the incorruptible body, however unequal to the rest otherwise, is equally incorrupt. For the hand, e.g., is not more incorrupt than the finger because it is larger than the finger; so, though finger and hand are unequal, their incorruptibility is equal. Thus, although incorruptibility is inseparable from an incorruptible body, yet the substance of the body is one thing, the quality of incorruption another. And therefore the body is not what it has. The soul itself, too, though it be always wise (as it will be eternally when it is redeemed), will be so by participating in the unchangeable wisdom, which it is not; for though the air be never robbed of the light that is shed abroad in it, it is not on that account the same thing as the light. I do not mean that the soul is air, as has been supposed by some who could not conceive a spiritual nature; but, with much dissimilarity, the two things have a kind of likeness, which makes it suitable to say that the immaterial soul is illumined with the immaterial light of the simple wisdom of God, as the material air is irradiated with material light, and that, as the air, when deprived of this light, grows dark, (for material darkness is nothing else than air wanting light,) so the soul, deprived of the light of wisdom, grows dark.