Romans 9:32

Wherefore? because they sought it not by faith
The question is asked, why they did not attain to that, which with so much diligence they pressed after? the answer is, because, as they did not seek for righteousness in a right place, or object, they sought for it in the law, and the works of it, where it is never to be found by a sinful creature, and not in Christ, in whom only are righteousness and strength; so they did not seek for it in a right way, by faith in Christ, without which it is impossible to please God, and by which only true righteousness is discerned and received:

but as it were by the works of the law;
not by works which looked like works of the law, and were not; but they sought it as if they expected their justification before God was to be by works of righteousness done by them; or as if it was partly by their own works, and partly by the goodness of God, accepting of them for a justifying righteousness. The Alexandrian Copy, and some others, read only, "as it were by works"; and so does the Vulgate Latin version: another reason, or else a reason of the former is,

for they stumbled at that stumbling stone;
meaning the word of the Gospel, at which Peter says they stumbled, and particularly the doctrine of justification by the righteousness of Christ; or rather Christ himself, who was "to the Jews a stumbling block, and to the Greeks foolishness", ( 1 Corinthians 1:23 ) .