Wherefore? Because they sought it not by faith, but as it were by the works of the law. For they stumbled at that stumblingstone;
Wherefore? Because [they sought it] not by faith, but as it were (rather simply, 'as') by the works of the law - as being thus attainable, which justification is not. Since, therefore, it is attainable only by faith, they missed it.
For (it is more than doubtful whether this "for" stood originally in the text; but it was very natural to insert it)
They stumbled at that stumblingstone, х lithon (G3037) proskommatos (G4348)] - better, 'against the stone of stumbling, meaning Christ. But in this they only did,