CXXXVII. The Bitter Memory of Babylon. The vivid picture of the exiles in their home-sickness, the mockery of their foreign masters, their love for Zion, the mention of Edom, and the savage thirst for vengeance, all go far to justify the supposition that the Ps. was written not very long after the destruction of Jerusalem by the Babylonians in 586.
Psalms 137:1-3. The day's work being over, the Jews sit by one of the many canals between the Tigris and Euphrates. Fain would they play and sing but they cannot, and they hang their harps on the poplar-trees (Populus euphratica). In vain their oppressors ask them for a song of Zion. They cannot sing Yahweh's songs in a land which is not Yahweh's. They cannot forget they are Jews: sooner may their right hand wither (Psalms 137:5 emended) than they cease to set their joy in Jerusalem above all other joy.
Psalms 137:7-9. The singer denounces the Edomites to Yahweh for their joy in the overthrow of Jerusalem (see Ezekiel 25:12 ff., Obadiah 1:10 ff.) and ends in furious tirade against Babylon the destroyer (so read in Psalms 137:8).