18. And knowest his will, and approvest things excellent, etc. He now concedes to them the knowledge of the divine will, and the approval of things useful; and this they had attained from the doctrine of the law. But there is a twofold approval, — one of choice, when we embrace the good we approve; the other of judgment, by which indeed we distinguish good from evil, but by no means strive or desire to follow it. Thus the Jews were so learned in the law that they could pass judgment on the conduct of others, but were not careful to regulate their life according to that judgment. But as Paul reproves their hypocrisy, we may, on the other hand, conclude, that excellent things are then only rightly approved (provided our judgment proceeds from sincerity) when God is attended to; for his will, as it is revealed in the law, is here appointed as the guide and teacher of what is to be justly approved. (79)
(79) There are two expositions of the words, δοκιμάζεις τὰ διαφερόντα, which may be sustained according to what the words signify in other places. The first word means to prove, or test, or examine, and also to approve; and the second signifies things which differ, or things which are excellent. “Thou provest, or, distinguishest things which differ,” is the rendering of [ Beza ] , [ Pareus ] , [ Doddridge ] , and [ Stuart ] : “Thou approvest things excellent or useful,” is the rendering of [ Erasmus ] , [ Macknight ] , and others. The first is the most suitable to the context, as knowledge, and not approval, is evidently intended, as proved by the explanatory clause which follows, — “being instructed out of the law.” — Ed.