Why? Because they sought it not by faith, but as it were by the works of the law. For they stumbled at that stumbling stone;
All Commentaries on Romans 9:32 Go To Romans 9
Tertullian of Carthage
AD 220
Of the passion itself should be figuratively set forth in predictions; and the more incredible (that mystery), the more likely to be "a stumbling-stone".
and knowing how to bear infirmity: "to wit as having been set by the Father "for a stone of offence"