Ps 120:4

“We attribute to God, as it were, every state that corresponds to our circumstances. For this reason, when we are half asleep and behaving slothfully, God, since he judges us unworthy of his observant watchfulness over us, is said to be asleep. But, when, after noticing at some time the harm that comes from his sleeping, we shall say, "Arise, why do you sleep, O Lord?" "Behold, he shall neither slumber nor sleep at that time, that keeps Israel." Some others, as it were, turn their eyes away from God because of their shameful deeds and their acts unworthy of the eyes of God. These, on repenting, say, "Why do you turn your face away?" Besides these, there are others who have cast out the memory of God and, as it were, are producing in him forgetfulness of themselves, and these say, "Why do you forget our want and our trouble?" In a word, people do the very things that are humanly spoken about God, making God behave in ways appropriate to the manner in which they have been made. Therefore, "I will extol you, O Lord, for you have upheld me; and you have not made my enemies to rejoice over me." And I will suffer nothing low or abject in my life.”

“[Daniel 4:13-14] "'And behold, a watchman and a holy one descended from heaven, and he cried out with a loud voice and spoke as follows: 'Cut down the tree and chop off its branches...'" Instead of "watchman" Theodotion uses the Chaldee word itself, hir, which is written with the three letters 'ayin, yodh, and resh. But it signifies the angels, because they ever keep watch and are prepared to carry out God's command. And so we too follow the example of the angels in their duties when we engage in frequent night-long vigils. Also it is said of the Lord: "He who keepeth Israel will neither slumber nor sleep" (Psalm 121:4). Lastly, we read a little later:”

“Choose for yourself Him, who will neither sleep nor slumber, and your foot shall not be moved. God is never asleep: if you dost wish to have a keeper who never sleeps, choose God for your keeper. "Suffer not my feet to be moved," you say, well, very well: but He also says unto you, "Let not him that keeps you slumber." Thou perhaps wast about to turn yourself unto men as your keepers, and to say, whom shall I find who will not sleep? What man will not slumber? Whom do I find? Whither shall I go? Whither shall I return? The Psalmist tells you: "He that keeps Israel, shall neither slumber nor sleep" [Psalm 121:4]. Do you wish to have a keeper who neither slumbers nor sleeps? Behold, "He that keeps Israel shall neither slumber nor sleep:" for Christ keeps Israel. Be thou then Israel. What means Israel? It is interpreted, Seeing God. And how is God seen? First by faith: afterwards by sight. If you can not as yet see Him by sight, see Him by faith...Who is there, who will neither slumber nor sleep? When you seek among men, you are deceived; you will never find one. Trust not then in any man: every man slumbers, and will sleep. When does he slumber? When he bears the flesh of weakness. When will he sleep? When he is dead. Trust not then in man. A mortal may slumber, he sleeps in death. Seek not a keeper among men.”

“Not without reason, brothers. For Samaritan is interpreted as guard. He knew that he was our guard. For "he neither slumbers nor sleeps, who guards Israel," and "Unless the Lord guard the city, in vain do they who guard watch." He who is our Creator is our guard. For did it suit him that we be redeemed but not that we be saved?”

“Regarding the divine nature the prophet David says, "Behold, he who keeps Israel shall neither slumber nor sleep." But the narrative of the Evangelist describes the Master Christ as sleeping in the boat. Now not sleeping and being asleep are two contrary ideas, so the prophet contradicts the Gospels if, as they argue, the Master Christ was God alone. There is no contradiction, for both prophecies and Gospels flow from one and the same spirit. The Master Christ therefore had a body, akin to all other bodies, affected by the need of sleep. So the argument for the confusion is proved a fable.Regarding the divine nature the prophet Isaiah said, "He shall neither be hungry nor weary" and so on. But the Evangelist says, "Jesus, being weary with his journey, sat thus by the well";23 and "shall not be weary" is contrary to "being weary." Therefore the prophecy is contrary to the narrative of the Gospels. But they are not contrary, for both are descriptive of one God. Not being weary is proper to the uncircumscribed nature that fills all things. But moving from place to place is proper to the circumscribed nature. When that which moves is constrained to travel, it is subject to the weariness of the wayfarer. Therefore what walked and was weary was a body, for the union did not confound the natures.”