Ellicott's Commentary for English Readers
This little song, with its appeal and its response, fitly closes the Songs of the Steps. It is a challenge to the Levites going on duty for the night to praise Jehovah, as others have already done by day. For the importance of this psalm in deciding the date of the close of the Psalter, see General Introduction.
A Song of degrees. Behold, bless ye the LORD, all ye servants of the LORD, which by night stand in the house of the LORD.(1) All ye servants.—We learn from 1Chronicles 9:33 that there were Levites whose duties brought them to the Temple by night. Moreover, the word ‘āmad, “stand,” is the customary word for sacerdotal service (Deuteronomy 10:8; Deuteronomy 18:7; 1Chronicles 23:30, &c).
Lift up your hands in the sanctuary, and bless the LORD.(2) Lift up your hands (see Note, Psalm 28:2) (in) the sanctuary.—The usual meaning would be to the sanctuary (see reference above), but since the servants of Jehovah are here addressed as standing in the sanctuary, this direction seems unreasonable. Render, therefore, in holiness, and comp. “lifting up holy hands” (1Timothy 2:8).
The LORD that made heaven and earth bless thee out of Zion.(3) Made heaven and earth.—For this style, as frequent in this group of psalms, see Psalm 121:2.