3 He will not suffer thy foot to stumble. Here the Prophet, in order to recall the faithful to the right path, and to defeat the influence of all the allurements which are wont to distract their minds, affirms that whatever advantages worldly men are accustomed to desire or hope for from the world, true believers will find abundantly and at hand in God alone. He not only attributes power to God, but also teaches that He is so affectioned towards us, that he will preserve us in all respects in perfect safety. As often as the power of God is extolled, there are many who immediately reply, It is very true that he can do such and such things if he is so inclined, but we do not certainly know what is his intention. In this passage, therefore, God is exhibited to the faithful as their guardian, that they may rest with assured confidence on his providence. As the Epicureans, in imagining that God has no care whatever about the world, extinguish all piety, so those who think that the world is governed by God only in a general and confused manner, and believe not that he cherishes with special care each of his believing people, leave men’s minds in suspense, and are themselves kept in a state of constant fluctuation and anxiety. In short, never will the hearts of men be led in good earnest to call upon God, until a persuasion of the truth of this guardianship is deeply fixed in their minds. The Psalmist declares that the purpose for which God is our keeper, is, that he may hold us up. The Hebrew word, מוט, mot, which is here used, signifies both a sliding or falling, and a trembling or staggering. Now, although it often happens that the faithful stagger, yea, are even ready to fall altogether, yet as God sustains them by his power, they are said to stand upright. And as amidst the many dangers which every moment threaten us, it is difficult for us to get rid of all anxiety and fear, the Prophet at the same time testifies, that God keeps watch unceasingly over our safety.

4. Behold! he who keepeth Israel will not slumber nor sleep. ⁶⁴⁶⁴     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. 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.