A Song of degrees
Literally, "of ascents." Perhaps chanted by the people as they went up to Jerusalem to the feasts. See, for example (Psalms 112:1); (Psalms 112:2).
Related Commentaries of Psalms 134:1
Psalms 134:1
1 Behold, bless ye the LORD, all ye servants of the LORD, which by night stand in the house of the LORD.