1 When the Jews were asked (as we have just now heard out of the Gospel when it was being read), how our Lord Jesus Christ, whom David himself called his Lord was David's Son, they were not able to answer. For what they saw in the Lord, that they knew. For He appeared to them as the Son of man; but as the Son of God He was hidden. Hence it was, that they believed that He could be overcome, and that they derided Him as He hung upon the Tree, saying, “If He be the Son of God, let Him come down from the Cross, and we will believe in Him.” They saw one part of what He was, they knew not the other, “For had they known Him, they would not have crucified the Lord of glory.” Yet they knew that the Christ was to be the Son of David.
For even now they hope that He will come. They know not that He has come already, but this their ignorance is voluntary. For even if they did not acknowledge Him on the tree, they ought not to have failed to acknowledge Him on His Throne. For in whose Name are all nations called and blessed, but in His whom they think not to have been the Christ? For this Son of David, that is, “of the seed of David according to the flesh,” is the Son of Abraham. Now if it was said to Abraham, “In your seed shall all nations be blessed;” and they see now that in our Christ are all nations blessed, why wait they for what is already come, and fear not that which is yet to come?
For our Lord Jesus Christ, making use of a prophetic testimony to assert His authority, called Himself “the Stone.” Yea such a stone, “that whosoever shall stumble against it shall be shaken; but on whomsoever it shall fall, it shall grind him to powder.” For when this stone is stumbled against, it lies low; by lying low, it “shakes” him that stumbles against it; being lifted on high, by its coming down it “grinds” the proud “to powder.” Already therefore are the Jews “shaken” by that stumbling; it yet remains that by His Glorious Advent they should be “ground to powder” also, unless perhaps while they are yet alive, they acknowledge Him that they die not. For God is patient, and invites them day by day to the Faith.
Source: Sermons on Selected Lessons of the New Testament (New Advent)