As it is written,
Behold, I lay in Zion a stumbling stone and rock of offense: and whosoever believes on him shall not be ashamed.
Read Chapter 9
There are many passages of Scripture where Christ is portrayed as a rock or a stone. The prophet Daniel calls him a stone which detaches itself without hands from the mountain, hitting and threatening all the kingdoms and filling the whole earth. This clearly refers to Christ. And in the law the rock from which the waters flowed is called Christ, as the apostle Paul himself testifies. And the apostle Peter says to the Jews: “This is the stone which the builders rejected.” The Jews did not want to compare Christ’s words with his deeds lest perhaps they might recognize that it was not absurd for him to say that he had come down from heaven…. This was the rock of offense as far as the Jews were concerned. The rock was undoubtedly the human flesh of the Savior. It detached itself without hands, because it was made of a virgin by the Holy Spirit without the participation of a male. Commentary on Paul’s Epistles. ...
Why then have not the Jews been justified? because they stumbled at the stumbling-stone: that is, the doctrine of Christ crucified has been a scandal to the Jews, at which being offended, they would not own him for their Messias. Yet whosoever believeth in him, and follows his law and doctrine, shall not be confounded, but obtain justification and salvation. (Witham) ...
This is said not of the Jews only but of the entire human race…. The wonder is that the prophet speaks not only of those who will believe but also of those who will not believe. For to stumble is to disbelieve.
It was fitting that the mystery of the passion should be set forth in predictions, for the more incredible it was, the more likely it was to have been a stumbling stone if it had been openly predicted.