4 Ah! unfruitful tree, mock not, because you are yet spared; the axe is delayed, be not secure; He will come and you shall be cut down. Believe that He will come. All these things which now ye see, once were not. Once the Christian people were not over the whole world. It was read of in prophecy, not seen in the earth; now it is both read and seen. Thus was the Church herself completed. It was not said to her, “See, O daughter, and hear;” but, “Hear and see.” Hear the predictions, see the completions.
As then, my beloved Brethren, Christ had once not been born of a Virgin, but His birth was promised, and He was born; He had once not done His miracles, they were promised, and He did them: He had not yet suffered, it was promised, and so it came to pass: He had not risen again, it was foretold, and so fulfilled: His Name was not throughout the world, it was foretold, and so fulfilled: the idols were not destroyed and broken down, it was foretold, and so fulfilled: heretics had not assailed the Church, it was foretold, and so fulfilled.
So also the Day of Judgment is not yet, but seeing it has been foretold, it shall be fulfilled. Can it be that He who in so many things has shown Himself true, should be false touching the Day of Judgment? He has given us a bond of His promises. For God has made Himself a debtor, not by owing ought, that is, not by borrowing; but by promising. We cannot therefore say to Him, “Give back what You have received.” Since “who has first given to Him, and it shall be recompensed unto him again?” We cannot say to Him, “Give what You have received;” but we say without scruple, “Give what You have promised.”
Source: Sermons on Selected Lessons of the New Testament (New Advent)