16. ἄρα οὖν. It follows therefore on a consideration of the whole circumstances—a combination very frequent in Rom. (8) and once each in Gal., Ephesians , 1 and 2 Thes. only.
οὐ τοῦ θέλοντος κ.τ.λ. Sc. ἡ ἐκλογή ἐστιν: the choice for the particular service depends not on man’s will or effort, but on GOD’S mercy.
τρέχειν. Metaph. only in S. Paul and Heb 12:1. Cf. περιπατεῖν.