31. νόμον οὖν κ.τ.λ. An anticipatory caution, worked out in ch. 6. The Gospel does not abolish law by insisting on faith as man’s sole contribution; it represents law as fulfilled in Christ, and in man if he has faith in Christ; see above on νόμου πίστεως. Practically a summary of the treatment of law in Matthew 5 νόμος here is not limited to, though it includes, the Mosaic law.
ἱστάνομεν. A later form of ἵστημι; cf. Thackeray, p. 247; Moulton, p. 55. Only here simpl.; cf. Act 17:15 (καθ.); 1Co 13:2 (μεθ.). συνιστάνω, 2Co 3:1; 2Co 4:2; 2Co 5:12; 2Co 6:4; 2Co 10:12; Gal 2:18.
The difficulty of this passage lies in its condensation; the clue is found when we see in it a return to Rom 1:17, and amplification of that passage, with a view to fuller exposition in chh. 5 ff.; in fact it restates the subject of the Epistle. In interpreting, we must bear in mind, as we saw on Rom 1:17, that Christ Jesus is throughout the concrete righteousness of GOD.