The Enarrations, or Expositions, on the Psalms

^10. Therefore, “Today if you will hear His voice, harden not your hearts”. O my people, the people of God! God addresses His people: not only the people of His which He shall not cast off, but also all His people. For He speaks in the corner stone to each wall: that is, prophecy speaks in Christ, both to the people of the Jews, and the people of the Gentiles. For some time ye heard His voice through Moses, and hardened your hearts. He then, when you hardened your hearts, spoke through a herald; He now speaks by Himself, let your hearts soften. He who used to send heralds before Him, has now deigned to come Himself; He here speaks by His own mouth, He who used to speak by the mouths of the Prophets.

11. “As in the provocation, and in the day of temptation in the wilderness, where your fathers proved Me”. Let such be no more your fathers: imitate them not. They were your fathers, but if you do not imitate them, they shall not be your fathers: yet as you were born of them, they were your fathers. And if the heathen who came from the ends of the earth, in the words of Jeremias, “The Gentiles shall come unto You from the ends of the earth, and shall say, Surely our forefathers have inherited lies, vanity, and things wherein there is no profit:” if the heathen forsook their idols, to come to the God of Israel; ought Israel whom their own God led from Egypt through the Red Sea, wherein He overwhelmed their pursuing foes; whom He led out into the wilderness, fed with manna, never took His rod from correcting them, never deprived them of the blessings of His mercy; ought they to desert their own God, when the heathen have come unto Him? When your fathers tempted Me, proved Me, and saw My works....

12. “Forty years long was I very near unto this generation, and said, It is a people that do always err in their hearts; for they have not known My ways”. The forty years have the same meaning as the word “always.” For that number forty indicates the fullness of ages, as if the ages were perfected in this number. Hence our Lord fasted forty days, forty days He was tempted in the desert, and forty days He was with His disciples after His resurrection. On the first forty days He showed us temptation, on the latter forty days consolation: since beyond doubt when we are tempted we are consoled. For His body, that is, the Church, must needs suffer temptations in this world: but that Comforter, who said, “Lo, I am with you always, even unto the end of the world,” is not wanting. For this was I with them forty years, to show such a race of men, which always provokes Me, even unto the end of the world: because by those forty years He meant to signify the whole of this world's duration.

13....We began with exulting joy: but this Psalm has ended with great fear: “Unto whom I swore in My wrath, that they should not enter into My rest”. It is a great thing for God to speak: how much greater for Him to swear? You should fear a man when he swears, lest he do somewhat on account of his oath against his will: how much more should you fear God, when He swears, seeing He can swear nought rashly? He chose the act of swearing for a confirmation. And by whom does God swear? By Himself: for He has no greater by whom to swear. By Himself He confirms His promises: by Himself He confirms His threats. Let no man say in his heart, His promise is true; His threat is false: as His promise is true, so is His threat sure. You ought to be equally assured of rest, of happiness, of eternity, of immortality, if you have executed His commandments; as of destruction, of the burning of eternal fire, of damnation with the devil, if you have despised His commandments....