The content of this particular “song of ascents” does not seem to be one that would fit the circumstance of going up to Jerusalem for worship. It was directed to those who served at the house of YHWH.
All those serving at the temple are called upon to bless or praise YHWH, with special reference to those Levites who guarded the sacred area during the night. This is a refrain that, in the hearing of the Levites who remained behind, the worshipers might have sung as they were about to depart from the temple courtyard.
The servants of YHWH were to lift up their hands, probably with arms raised and open palms in an attitude of prayer. When doing so, they would have been facing the holy place or temple and blessing or praising YHWH. This refrain, too, could have been one the departing worshipers would sing.
Likely, in response, the Levites would raise their voice in song, petitioning that YHWH’s blessing be upon the worshipers. As the place where the temple was located, Zion proved to be YHWH’s representative place of dwelling. Therefore, his blessing would come from Zion. That Zion served only as his representative place of dwelling is reflected in the words that identify him as the Maker of heaven and earth, the dome-like sky and the land area known to the psalmist.
Regarding YHWH, see Psalm 1.
The extant Septuagint reading, though similar in content, differs in expression. “Now look! Bless the Lord, all servants of the Lord who are standing in the house of the Lord, in the courtyards of the house of our God. In the nights, raise your hands to the holy places and bless the Lord. May the Lord bless you from Zion [or, according to another reading, ‘The Lord will bless you’], [the Lord] who made the heaven and the earth.”
In the largest Dead Sea Psalms Scroll, verse 3 reads, “name of YHWH.” The word “name,” however, is not included in the Masoretic Text, the Septuagint, and the Vulgate.