John Gill's Exposition of the Whole Bible
Psalms 134 - Introduction
INTRODUCTION TO PSALM 134
A Song of degrees. This is the last of the psalms called "songs of degrees"; of which Psalms 120:1, title. It is thought to be written by David, either when he brought the ark to Zion, 2 Samuel 6:17; or rather when he numbered the Levites, and appointed them their service, 1 Chronicles 23:26. So the Syriac inscription,
"a psalm" of David, concerning the priests, whom he appointed to wait on the ministry of the Lord in the nights; but, spiritually, an instruction of life.''
Aben Ezra connects it with the preceding psalm,
"as the dew of Hermon ye shall be that bless; behold, therefore, ye are bound to bless the Lord?''