Albert Barnes' Bible Commentary
Psalms 121 - Introduction
This psalm is entitled simply, “A Song of Degrees.” See the notes on the title to Psalms 120:1. Nothing is known, or can be known, of the author or of the occasion on which it was composed. DeWette and Rosenmuller suppose that it was composed in the exile; Rosenmuller regarding it as a psalm to be sung on the return to Palestine after the captivity - DeWette, as the psalm of a pensive exile looking toward the hills of Palestine, his native land, as the source from where all his help must come - and expressing confidence in God that he would bring him out of his exile and his trouble. There is no proof, however, that either of these suppositions is correct. The language is such, indeed, as might then be employed, but it is also such as might be used on many other occasions. It might be the language of the leader of an army, endangered, and looking to the “hills” where he expected reinforcements; it might be that of a pious man encompassed with dangers, anal using this expression as illustrative of his looking up to God; or it might be the language of one looking directly to heaven, represented as the heights, or the exalted place where God dwells; or it might be the language of one looking to the hills of Jerusalem - the seat of the worship of God - the place of His abode - as his refuge, and as the place from where only help could come. This last seems to me to be the most probable supposition; and thus the psalm represents the confidence and hope of a pious man (in respect to duty, danger, or trial) as derived from the God whom he worships - and the place where God has fixed his abode - the church where he manifests himself to people.