Charles H. Spurgeon on Psalms 121:7

It is of importance to mark the reason why the prophet repeats so often what he had so briefly and in one word expressed with sufficient plainness. Such repetition seems at first sight superfluous: but when we consider how difficult it is to correct our distrust, it will be easily perceived that he does not improperly dwell upon the commendation of the divine providence. How few are to be found who yield to God the honour of being a "keeper", in order to their being thence assured of their safety, and led to call upon him in the midst of their perils! On the contrary, even when we seem to have largely experienced what this protection of God implies, we yet instantly tremble at the noise of a leaf falling from a tree, as if God had quite forgotten us. Being then entangled in so many unholy misgivings, and so much inclined to distrust, we are taught from the passage that if a sentence couched in a few words does not suffice us, we should gather together whatever may be found throughout tim whole Scriptures concerning the providence of God, until this doctrine —"That God always keeps watch for us" —is deeply rooted in our hearts; so that, depending upon his guardianship alone, we may bid adieu to all the vain confidences of the world. —John Calvin.