v. 8a — Address and destiny
“Daughter Babylon” personifies the city/people. The phrase “doomed to destruction” frames Babylon’s downfall as anticipated.
v. 8b–c — The one called “blessed”
The psalm declares the person who “repays” Babylon. The repayment is explicitly proportional: it corresponds to what Babylon “served” to the speaker’s community.
v. 9 — The retaliatory image
The “blessed” one is described as the one who Babylon’s infants and smashes them against a rock. The verse intensifies the retaliatory logic with a concrete, horrifying wartime picture.