Psalm 137
1 By the rivers of Babylon, there we sat down, yea, we wept, when we remembered Zion.
2 We hanged our harps upon the willows in the midst thereof.
3 For there they that carried us away captive required of us a song; and they that wasted us required of us mirth, saying, Sing us one of the songs of Zion.
4 How shall we sing the Lord's song in a strange land?
5 If I forget thee, O Jerusalem, let my right hand forget her cunning.
6 If I do not remember thee, let my tongue cleave to the roof of my mouth; if I prefer not Jerusalem above my chief joy.
7 Remember, O Lord, the children of Edom in the day of Jerusalem; who said, Rase it, rase it, even to the foundation thereof.
8 O daughter of Babylon, who art to be destroyed; happy shall he be, that rewardeth thee as thou hast served us.
9 Happy shall he be, that taketh and dasheth thy little ones against the stones.
The psalm is a hymn expressing the needs of the Jewish people in exile following the Babylonian conquest of Jerusalem in 607 BCE.
The rivers of Babylon are the Euphrates river, its tributaries, and the Tigris river.
In its whole form, the psalm reflects the yearning for Jerusalem as well as hatred for the Holy City's enemies with sometimes violent imagery.
It describes the sadness of the Israelites, asked to "sing the Lord's song in a foreign land". This they refuse to do, leaving their harps hanging on trees. The poem then turns into self-exhortation to remember Jerusalem.