Summary
Exiles sit by irrigation canals with their instruments hung in the willows, asked by their captors for one of the songs of Zion as entertainment. They refuse: the LORD’s song is not sung in a strange land for sport. Then the psalm turns from refusal to oath — if I forget Jerusalem, let my right hand forget its skill and my tongue stick to my palate.
The last three verses are not a plan but a sentence, spoken in the form of a beatitude: Edom, who cheered the razing, is remembered; Babylon is addressed as one already appointed to destruction, and the man who executes the appointed judgment is called blessed. The psalm forbids the singer to take up the sword and gives him instead the harder thing — to prefer Jerusalem above his own chief joy, and to leave the reckoning where it belongs.
Outline
Weeping by the waters of Babylon; the captors ask for a song of Zion; how shall we sing the LORD’s song in a strange land?
If I forget you, Jerusalem, let my right hand lose its skill — if I do not set you above my chief joy.
Remember Edom’s cry, Raze it; Babylon is addressed as appointed to destruction, and the executor of that judgment is called blessed.
Stanza divisions provisional — to be conformed to the Book of Psalms for Worship. References NASB.