20. τῇ γὰρ ματαιότητι = the purposelessness, futility which the world of nature exhibits, until the conception of nature is itself brought under the larger conception of GOD’S eternal providence.
ὑπετάγη. Prob. ref. Gen 3:17-18.
διὰ τὸν ὑποτάξαντα = for the purposes of Him who so subjected it; cf. on Rom 5:10, Heb 2:10. S. Paul here connects the actual condition of nature with the Fall, as he does the actual condition of human nature in c. 5., no doubt in dependence on Gen 3:17.
ἐφ' ἑλπίδι with ὑπετάγη. The subjection to vanity is a commonplace: the novelty here lies in the vision of hope.