Psalm 137

By the rivers of Babylon we sat and wept when we remembered Zion.

There on the poplars we hung our harps,

for there our captors asked us for songs, our tormentors demanded songs of joy; they said, “Sing us one of the songs of Zion!”

How can we sing the songs of the Lord while in a foreign land?

If I forget you, Jerusalem, may my right hand forget its skill.

May my tongue cling to the roof of my mouth if I do not remember you, if I do not consider Jerusalem my highest joy.

Remember, Lord, what the Edomites did on the day Jerusalem fell.

“Tear it down,” they cried, “tear it down to its foundations!”

Daughter Babylon, doomed to destruction, happy is the one who repays you according to what you have done to us. Happy is the one who seizes your infants and dashes them against the rocks.

For context, the book of Psalms is a collection of jewish hymns. Psalm 137 is written from the viewpoint of defeated jews in Babylonian exile; the last verse may well be read as a defiant answer to the line "sing us one of the songs of zion!". The god of the bible is not speaking directly here nor is he being addressed.

As additional context, Boney M's disco version is actually a cover version of The Melodians "Rivers of Babylon" (featured on the soundtrack of the film The Harder They Come) and tactfully omits the verse about dashing Babylonian infants against rocks.