Psalm 137

Psalm 137 (Greek numbering: Psalm 136) is one of the best known of the Biblical psalms. Its opening lines, "By the rivers of Babylon..." (Septuagint: "By the waters of Babylon...") have been set to music on several occasions.

The psalm is a hymn expressing the yearnings 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 (possibly the river Habor, the Chaboras, or modern Khabur, which joins the Euphrates at Circesium). 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. Rabbinical sources attributed the poem to the prophet Jeremiah, and the Septuagint version of the psalm bears the superscription: "For David. By Jeremias, in the Captivity."

The early lines of the poem are very well known, as they describe 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. "If I forget thee, O Jerusalem, let my right hand forget her cunning..." (אִם-אֶשְׁכָּחֵךְ יְרוּשָׁלִָם--תִּשְׁכַּח יְמִינִי) It ends with prophetic predictions of violent revenge, telling a "Daughter of Babylon" of the delight of "he who seizes your infants and dashes them against the rocks" (New International Version).

Since the Middle Ages, this Psalm 137 was performed at the Vespers celebration of Wednesday, according to the rule of St. Benedict, set in 530AD

...
Wikipedia