Albert Barnes Commentary Psalms 134:2

"Lift up your hands to the sanctuary, And bless ye Jehovah." — Psalms 134:2 (ASV)

Lift up your hands in the sanctuary - Margin, In holiness. The Hebrew word properly means holiness, but it may be applied to a holy place. See (Psalms 20:2). The lifting up of the hands is properly expressive of prayer, but the phrase may be used to denote praise or worship in general.

And bless the Lord - In the night-watches - while all around is still, - let there be one place where the voice of praise shall ascend on high.