What does Psalm 134:2 mean?

This call to worship (Psalm 134:1) is extended to the priests and Levites. They served at all times in the temple (Leviticus 8:35).

To lift one's hands is a common Old Testament expression of praise. David spoke of lifting hands towards the Lord's sanctuary (Psalm 28:2). Paul also mentions this as an aspect of worship when giving instructions to Timothy (1 Timothy 2:8). References to "the holy place" or "the sanctuary" mean the physical center of Old Testament worship. At first, this was the holy place within the tabernacle (Exodus 26:33–34). Later, it was the holy place built as part of the temple in Jerusalem (1 Kings 6:1). Even when the temple had been destroyed (2 Chronicles 36:17–21), the prophet Daniel still preferred to face Jerusalem when he prayed (Daniel 6:10).