I do not understand the last lines of psalm 137 ("By the rivers of Babylon"/"Al naharos bovel," the psalm recited before Birkat Ha-Mazon on weekdays. [It includes the famous lines "Im eshkachech Yerushalayim tishkach yemini."--"If I forget you, O Jerusalem, let my right hand forget its skill."]). These lines read:
בת־בבל השדודה אשרי שישלם־לך את־גמולך שגמלת לנו׃
אשרי שיאחז ונפץ את־עלליך אל־הסלע
...Alternately translated as:
"O violated daughter of Babylon -- praiseworthy is he who repays you in accordance with the manner that you treated us. Praiseworthy is he who will clutch and dash your infants against the rock."
(Artscroll Ashkenaz siddur)
and
"O daughter of Babylon, that art to be destroyed; happy shall he be, that repayeth thee as thou hast served us. Happy shall he be, that taketh and dasheth thy little ones against the rock."
Please tell me:
- Who is the "violated/to-be-violated daughter of Babylon?" (I assume this is either a metaphor or a metonymy.)
- What is happening to her and her child, and why do they deserve it?
- Why should we feel holy and ennobled when reciting this before bentching? (or, perhaps more to the point:
- Why was this psalm chosen to be sung before weekday bentching? Why is it reasonable?)
"happy shall be he"
is a specific reference to Darius, who visited cruelty upon Babylon. This verse is not an endorsement of his act, but rather a further insult to Babylon that its destroyer would become great.