7 “As we have heard, so have we seen”. Blessed Church! At one time you have heard, at another time you have seen. She heard in promises, sees in performance: heard in Prophecy, sees in the Gospel. For all things which are now fulfilled were before prophesied. Lift up your eyes then, and stretch them over the world; see now His “inheritance even to the uttermost parts of the earth:” see now is fulfilled what was said, “All kings shall fall down before Him: all nations shall serve Him:” see fulfilled what was said, “Be exalted, O God, above the heavens, and Your glory above all the earth.” See Him whose feet and hands were pierced with nails, whose bones hanging on the tree were counted, upon whose vesture lots were cast: see reigning whom they saw hanging; see sitting in Heaven whom they despised walking on earth: see thus fulfilled, “All the ends of the earth shall remember, and turn to the Lord, and all the kindreds of the nations shall worship before Him.”
Seeing all this, exclaim with joy, “As we have heard, so have we seen.” Justly the Church herself is so called out of the Gentiles....They to whom the Prophets were not sent, first heard and understood the Prophets: they who first heard not, afterwards hearing marvelled. They remained behind to whom they were sent, carrying the books, understanding not the truth: having the tables of the Testament, and not holding the inheritance. But we,...“As we have heard, so have we seen.” And where do you hear?
Where do you see? “In the city of the Lord of Hosts, in the city of our God. God has founded it for ever.” Let not heretics insult, divided into parties, let them not exalt themselves who say, “Lo, here is Christ, or lo, there.” Whoso says, “Lo, here is Christ, or lo, there,” invites to parties. Unity God promised. The kings are gathered together in one, not dissipated through schisms. But haply that city which has held the world, shall sometime be overthrown? Far be the thought! “God has founded it for ever.” If then God has founded it for ever, why do you fear lest the firmament should fall?
Source: The Enarrations, or Expositions, on the Psalms (New Advent)