Thomas Aquinas — on Rom 8:20 (Commentary on Romans)

“Then he explains this waiting, at "for the creature." First, the need to wait; second, its end, at "because the creature"; third, the sign of waiting, at "for we know that every creature." Now the need to wait is due to a defect to which the creature is subject. For a thing subject to no defect has no need to wait for something. He shows the creature's defect when he says: "for the creature was subjected to vanity." If by creature is understood the just man, he is understood to be subject to vanity, i.e., to those bodily things which are changeable and inclined to fail. Hence they are called vain: "vanity of vanities, and all is vanity" (Eccl 1:2). But he is subjected to them because the needs of the present life require that he occupy himself with them, not willingly, because he does not love such temporal things as those do against whom it is said: "how long will you love vanity and seek after lies?" (Ps 4:3). But this creature is subjected to such vanity by reason of him, i.e., by God's ordinance, who subjected it, i.e., the just man, to these sensible creatures; but in hope, namely, that at some time he will be freed from such occupation in the resurrection "when they neither marry nor are given in marriage, but are like the angels in heaven" (Matt 22:30). If by creature is understood human nature itself, then such a creature is subjected to vanity, i.e., to changeableness; "every man stands as a mere breath" (Ps 39:5). Not willingly, because such vanity is inflicted on human nature as a punishment. But punishment is involuntary just as guilt is voluntary. But human nature is subjected to such sufferings by reason of him, i.e., by the sentence of God, who subjected it, namely, human nature, to defects, but nevertheless in hope of the time when such sufferings will be avoided: "the thresher shall not thresh it forever" (Isa 28:28). But if by creature is understood sensible creation, then such creation was subjected to vanity, i.e., to changeability, but not willingly. For the defects which follow on changeableness, such as aging and ceasing to be and the like, are contrary to the particular nature of this or that thing which seeks self-preservation, although they are in keeping with the general nature of things. Nevertheless, the visible creature is subjected to such vanity by reason of him, i.e., by the ordinance of God who subjected it in hope, i.e., in expectation of a glorious renewal as was stated above.”