Ellicott's Commentary On The Whole Bible
Psalms 121 - Introduction
CXXI.
This simple but exquisite little hymn of four fourline verses, dwells almost exclusively on the sleepless guardianship of His people by the (God who made the world. An implied contrast with the idols of the heathen, “peradventure sleeping,” while their votaries pray (1 Kings 18:27), is felt in every verse. (See Note Psalms 121:1.) But it is only implied. The poet seems to want nothing to heighten his truthful confidence, neither vivid colouring nor elaborate imagery, nothing save the repetition again and again of the one word keep. (See Notes.) What a history were that, if it could be written, of the countless thousands of Christians who have been consoled in trouble or sickness by this psalm! Among others, it was read at the deathbed of Julius Hare. It is in this psalm that the steplike progression of the rhythm is most plainly marked.
Title. — The Hebrew, in many editions, presents a variation from the usual “song of degrees.” Here, “a song for the degrees” — a variation which has been claimed in support of two rival theories, since it favours equally the view which make these hymns pilgrim songs, and that which sees in them a reference to the actual steps leading up to the Temple.