"Endless Extinction Of Unhappy Hates"

Context: Twenty years have passed since Polyphontes, now tyrant of Messenia, murdered Cresphontes, the proper king, and forced Merope, the widow of the murdered monarch, to marry him; however, Polyphontes did not kill Merope's youngest son, Aepytus, who mysteriously disappeared. The drama opens as Aepytus, now an adult, returns to Messenia to take vengeance on his father's murderer; he comes with his uncle, Laias, who shows him the kingdom that belongs to him. His plan is to enter the palace as an unknown guest bringing word of his own death; in this way he will be able to kill Polyphontes when he least expects danger. But no sooner does he relate his plan than Merope and Polyphontes enter; she has come to Cresphontes' tomb to honor the twentieth anniversary of his death, but Polyphontes wants her to stop such mourning because her behavior is making the people uneasy. The quotation comes from Polyphontes' speech requesting Merope to stop her mourning:

All this I bear, for, what I seek, I know:
Peace, peace is what I seek, and public calm;
Endless extinction of unhappy hates,
Union cemented for this nation's weal.
And even now, if to behold me here,
This day, amid these rites, this black-robed train,
Wakens, O Queen! remembrance in thy heart
Too wide at variance with the peace I seek–
I will not violate thy noble grief,
The prayer I came to urge I will defer.