Augustine of Hippo : This is why Moses fasted for forty days, and Elijah, and the Mediator himself, our Lord Jesus Christ: because in this time-bound state of ours restraint from bodily attractions and allurements is very necessary. The people also spent forty years wandering in the desert, and forty days of rain produced the flood. The Lord spent forty days after his resurrection with his disciples, to convince them of the reality of his risen body. This suggests that in this life, in which we are in exile away from the Lord, the number forty stands, as I have just said, for our need to celebrate the memorial of the Lord's body, which we do in the church until he comes. — Sermon 51.32 Maximus of Turin : Fasting these forty days and nights, holy Moses too merited to speak with God, to stand and stay with him and to receive the precepts of the law from his hand. For although this human condition prevented him from seeing God, yet the grace of his fasting drew him into close contact with the Divinity. For to fast frequently is a portion of God's virtues in ourselves, since God himself always fasts. He is more familiar, intimate and friendly with the person in whom he sees more of his works, as Scripture says, "And Moses spoke with God face to face like one speaking with his friend." — Sermon 35.4 Origen of Alexandria : Every form of nourishment is called "bread" in the Scriptures. This is clear from what is written concerning Moses: for forty days he neither ate "bread" nor drank water. The word that nourishes is multidimensional and varied. Not everyone can receive the solid and strong nourishment of God's teachings. Therefore, wishing to give an athlete's nourishment suitable to the more perfect, [Christ] says, "The bread that I will give is my flesh, which I will give for the life of the world." — ON PRAYER 27.4