Ambrose of Milan
Catena Aurea · Lukasevangelium 4
And Jesus being full of the Holy Ghost returned from Jordan, and was led by the Spirit into the wilderness, Being forty days tempted of the devil. And in those days he did eat nothing: and when they were ended, he afterward hungered. And the devil said unto him, If thou be the Son of God, command this stone that it be made bread. And Jesus answered him, saying, It is written, That man shall not live by bread alone, but by every word of God.
But mark the mystical number of days. For you remember that for forty days the waters of the deep were poured forth, and by sanctifying a fast of that number of days, He brings before us the returningmercies of a calmer sky. By a fast of so many days also, Moses earned for himself the understanding of the law. Our fathers being for so many years settled in the wilderness, obtained the food of Angels.