Ps 134:1-3.1, 2. The pilgrim bands arriving at the sanctuary call on the priests, who
stand in the house of the Lord -- at the time of the evening sacrifice, to unite in praising God in their name and that of the people, using appropriate gestures, to which the priests reply, pronouncing the Mosaic blessing which they alone could pronounce. A fit epilogue to the whole pilgrim-book, Psalms 120-134.
by night -- the evening service (Ps 141:2), as opposed to morning (Ps 92:2).
2. Lift up your hands -- (Compare Ps 28:2).
3. After the manner directed (Nu 6:23).
out of Zion -- the Church, as His residence, and thus seat of blessings. Thus close the songs of degrees.