Psalms 95:10

"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" [Psalm 95:10]. 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, [Matthew 4:1-11] and forty days He was with His disciples after His resurrection. [Acts 1:3] 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," [Matthew 28:20] 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.

Did not the prophet, speaking in behalf of God, say to you, "Forty years I was offended with that generation, and I said, 'These always err in heart.' " How was it, then, that at that time God did not turn away from you? How is it that after you killed your children, after your idolatries, after your many acts of arrogance, after your unspeakable ingratitude, that God even allowed the great Moses to be a prophet among you and that he worked wondrous and marvelous signs himself? What happened in the case of no human being did happen to you. A cloud was stretched over you in place of a roof; a pillar instead of a lamp served to guide you; your enemies retreated of their own accord; cities were captured almost at the first battle shout. You had no need of weapons, no need of an army in array, no need to do battle. You had only to sound your trumpets, and the walls came tumbling down of their own accord. And you had a strange and marvelous food that the prophet spoke of when he exclaimed, "God gave them the bread of heaven. The people ate the bread of angels; he sent them provisions in abundance."

"See, O people, the grace of Christ about you. Even while you are harassed on earth, you have possessions in heaven. There, then, let your heart be, where your possession is." This is the rest that is due the just and is denied the unworthy. Wherefore says the Lord, "As I swore in my wrath, that they shall not enter into my rest." For they who have not known the ways of the Lord shall not enter into the rest of the Lord, but to the individual who has fought the good fight and has finished his course it is said, "Turn to your rest." It is a blessed rest to pass by the things of the world and to find repose in the celestial fellowship of the mysteries that are above the world. This is the rest toward which the prophet hastened, saying, "Who will give me wings like a dove and I will fly and be at rest?" The holy person knows that his rest is in heaven, and to this rest he says his soul must turn. Therefore his soul was in its rest, to which he says it must return. This is the rest of the great sabbath, in which each of the saints is above the sensible things of the world, devoting himself entirely to deep and invisible mystery and cleaving to God. This is that rest of the sabbath on which God rested from all the works of his world.