Sentence:  Ye wake no more to anguish;‥ ye have borne/ The Chosen, the Destroyer!‥ soon his hand/ Shall strike the <WSD>efficient</WSD> blow;/ Soon shaking off your penal forms, shall ye,/ With songs of joy, amid the Eden groves,/ Hymn the Deliverer's praise! 
Meaning of the word marked with <WSD> tags:  effective