Sentence:  Thus charg'd thy sire, which thou forgett'st: yet now those thoughts appease / That torture thy great spirit with wrath; which if thou wilt give surcease, / The king will <WSD>merit</WSD> it with gifts ; and if thou wilt give ear / I'll tell you how much he offers thee:—yet thou sitt'st angry here. 
Meaning of the word marked with <WSD> tags:  To reward.