Mark 12:10

(ubi sup.) But that this was done by Divine interposition he affirms, by immediately afterwards adding, And have ye not read this Scripture, The stone which the builders refused is become the head-stone in the corner? As if he had said, how is this prophecy to be fulfilled, save in that Christ, being rejected and slain by you, is to be preached to the Gentiles, who will believe on Him? Thus then as a corner stone, He will found the two people on Himself, and of the two people will build for Himself a city of the faithful, one temple. For the masters of the synagogue, whom He had just called husbandmen, He now calls builders, because the same persons, who seemed to cultivate His people, that they might bear the fruits of life, like a vineyard, were also commanded to construct and adorn this people, to be, as it were, a house worthy to have God for its inhabitant.

The stone then which the builders refused, the same has become the head-stone of the corner, that is, of the Church. For the Church is, as it were, the corner, joining together Jews and Gentiles; and this corner has been made by the Lord, and is wonderful in our eyes, that is, in the eyes of the faithful; for miracles meet with detraction from the faithless. The Church indeed is wonderful, as it were resting on wonders, for the Lord worked with the Apostles, and confirmed the word with signs. And this is what is meant, when it is said, This was the Lord's doing, and it is marvellous in our eyes.

This rejected stone, which is borne by that corner where the lamb and the bread met in the supper, ending the Old and beginning the New Testament, does things marvellous in our eyes as the topaz. (Ps. 118, Ps. 127. Vulg.)