Romans 9:32

Wherefore? Because they sought it not by faith, but as it were by works. They stumbled at the stone of stumbling.

For the true meaning of "as it were by works" see under Romans 9:11, where it means "not of fleshly descent" just as it certainly does here. That is the very thing Paul had been writing of throughout this portion of Romans, the Jews thinking to have salvation through fleshly descent from Abraham. Any attempt to view "works" here as the efforts of the Jews at keeping the law of Moses is incorrect. The total unrighteousness of the vast majority of that nation, called in scripture "worse than Sodom," and worse than the northern tribes, makes any such interpretation of "works" here to be absolutely untenable. The law of God given through Moses is precisely what they did not keep. They relied solely upon fleshly descent, as taught by John the Baptist, Christ, and Paul.

They stumbled at the stone of stumbling ... refers to their rejection of Christ; and for a full discussion of this subject, see below.