Behold! he who keepeth Israel will not slumber nor sleep. [1] To recall each individual to the consideration of the common covenant, he represents the Divine providence as extending to the whole body of the Church. In order that each of us for himself may be assured that God will be gracious to him, it behoves us always to begin with the general promise made to all God's people,. This form of expression, he will not slumber nor sleep, would be improper in other languages, according to the idiom of which it should rather be, He will not sleep, yea, he will not slumber: but when the Hebrews invert this order, they argue from the greater to the less. The sense then is, that as God never slumbers even in the smallest degree, we need not be afraid of any harm befalling us while he is asleep. The design of the Prophet is now obvious. To persuade true believers that God has a special care of each of them in particular, he brings forward the promise which God made to the whole people, and declares God to be the guardian of his Church, that from this general principle, as from a fountain, each might convey streams to himself. Accordingly immediately after, (Psalm 121:5,) addressing himself to each in particular, he repeats, Jehovah is thy keeper, that no person might hesitate to apply to himself that which belonged to the whole community of Israel. Besides, God is called a defense at the right hand, to teach us that it is not necessary for us to go far in seeking him, but that he is at hand, or rather stands at our side to defend us.

Footnotes

1 - A notion was prevalent among the heathen, that their gods sometimes slept, and were not then conscious of the wants of their worshippers. Elijah thus addressed in irony the followers of Baal, 1 Kings 18:27: "Cry aloud; for he is a god; either he is talking, or he is pursuing, or he is in a journey, or peradventure he sleepeth, and must be waked." Very different was the character of the guardian of Israel. He relaxed not his watchful care over his people by indulging in light slumbers during the day, nor even by sleeping in the night, when the tired frame of man seeks and demands repose.

Behold, he that keepeth Israel - The Keeper - the Guardian - of his people. The psalmist here passes from his own particular case to a general truth - a truth to him full of consolation. It is, that the people of God must always be safe; that their great Guardian never slumbers; and that he, as one of his people, might, therefore, confidently look for his protecting care.
Shall neither slumber nor sleep - Never slumbers, never ceases to be watchful. Man sleeps; a sentinel may slumber on his post, by inattention, by long-continued wakefulness, or by weariness; a pilot may slumber at the helm; even a mother may fall asleep by the side of the sick child; but God is never exhausted, is never weary, is never inattentive. He never closes his eyes on the condition of his people, on the needs of the world.

He that keepeth Israel - The Divine Being represents himself as a watchman, who takes care of the city and its inhabitants during the night-watches; and who is never overtaken with slumbering or sleepiness. There is a thought in the Antigone of Sophocles, that seems the counterpart of this of the psalmist,
Ταν σαν, Ζευ, δυναμιν τις ανδρων
Ὑπερβασια κατασχοι,
Ταν ουθ' ὑπνος αἱ -
ρει ποθ' ὁ παντογηρως,
Ακαματοι τε θεων
Μηνες;
Antig. ver. 613, Edit. Johnson.
Shall men below control great Jove above,Whose eyes by all-subduing sleep
Are never closed, as feeble mortals' are;But still their watchful vigil keep
Through the long circle of th' eternal year?
Franklin.

Behold, he that keepeth Israel shall neither slumber nor sleep. He that kept Israel or Jacob, when asleep, and appeared to him in a dream, and promised to keep him in all places, and did; who found his posterity in the wilderness, and kept them as the apple of his eye: he keeps his spiritual Israel, whom he has chosen, redeemed, and calls; and he that is in general their keeper, is the keeper of every particular believer, who may promise themselves the utmost safety under his care; since, though he may sometimes seem to sleep, when he withdraws his gracious presence, defers help, and does not arise so soon to the assistance of his people as they wish for and expect; yet does not in reality sleep, nor is any ways negligent of them; no, not so much as slumber, nor is in the least indifferent about them, and careless of them; see Genesis 28:15. So Homer (k) represents Jupiter as not held by sleep, while other gods and men slept all night; and hence Milton (l) has the phrase of "the unsleeping eyes of God": but the Phrygians had a notion that their god slept in winter, and was awake in summer (m).
(k) Iliad. 2. v. 1, 2. (l) Paradise Lost, B. 5. v. 647. (m) Plutarch. de Iside & Osir. prope finem.