A Psalm of Ascents. Psalm 121 is located in what is traditionally known as the Fifth Book of Psalms, comprising Psalms 107–150. Additionally, it belongs to a subset within the psalter known as the Psalms of Ascent (Psalms 120–134). This smaller grouping of fifteen poetic songs has long been associated with three pilgrimages to the Temple in Jerusalem to be made every year by Jewish males, as commanded in Exodus 23:14–17 and other verses of the Old Testament, which was and is the Hebrew Bible.
No matter where one’s point of origin might be, visiting Jerusalem was typically spoken of by the Jewish community as a process of “going up” to the city. Jerusalem is approximately 2,500 feet above sea level, and the coast of the Mediterranean Sea is only about 30 miles to the west. So any coastal route would involve a substantial ascent, 2,500 feet over a distance of 30 miles, which could be a reason the journey to Jerusalem was referred to as “going up.” The Psalms of Ascent were specifically chosen songs of worship and prayer sung and recited by pilgrims as they traveled “up to,” ascended, to the City of David (Jerusalem) and Mount Zion (the Temple) to participate in the pilgrimage festivals.
The three yearly pilgrimage festivals were: Passover (Feast of Unleavened Bread; March/April), Pentecost (Feast of the Harvest; May/June, 50 days after Passover) and Tabernacles/Booths (Feast of the Ingathering associated with the Fall harvest; September/October).