Ambrose of Milan, on Ps 136:8

“O daughter of Babylon, miserable: blessed shall he be who shall repay thee thy payment which thou hast paid us.”

“And David, pitying her, says, "O wretched daughter of Babylon." Wretched indeed, as being the daughter of Babylon, when she ceased to be the daughter of Jerusalem. And yet he calls for a healer for her and says, "Blessed is he who shall take your little ones and dash them against the rock." That is to say, shall dash all corrupt and filthy thoughts against Christ, who by his fear and his rebuke will break down all actions against reason, so as, if any one is seized by an adulterous love, to extinguish the fire, that he may by his zeal put away the love of a harlot and deny himself that he may gain Christ.”

Imported from an open dataset — not yet checked against the printed edition.