Romans 9:33

"As it is written, Behold I lay in Sion a stumbling-stone, and rock of offence: and whosoever believeth on Him shall not be ashamed." You see again how it is from faith that the boldness comes, and the gift is universal; since it is not of the Jews only that this is said, but also of the whole human race. For every one, he would say, whether Jew, or Grecian, or Scythian, or Thracian, or whatsoever else he may be, will, if he believes, enjoy the privilege of great boldness. But the wonder in the Prophet is that he foretells not only that they should believe, but also that they should not believe. For to stumble is to disbelieve. As in the former passage he points out them that perish and them that are saved, where he says, "If the number of the children of Israel be as the sand of the sea, the remnant shall be saved." And, "If the Lord of Sabaoth had not left us a seed, we should have been as Sodoma." And, "He hath called not of the Jews only, but also of the Gentiles;" so here too he implies that some will believe, and some will stumble. But stumbling comes of not taking heed, of gaping after other things. Since then they did give heed to the Law, they stumbled on the stone, "And a stone of stumbling and rock of offence" he calls it from the character and end of those that believe not.