Seen all their vengeance: their refers to the poet’s enemies, who are also the unnamed opponents in verses 58 and 59. Vengeance refers to repaying harm to someone who has supposedly committed an injustice. In this case their vengeance refers to the vengeful acts committed by the poet’s enemies to get even with him, to repay him for his evil. This explanation no doubt says more than the writer intends to say, since he believes that he has not committed evil against them; accordingly New Jerusalem Bible and the New American Bible (New American Bible) translate “their vindictiveness,” which means “their desire to get revenge.” Biblia Dios Habla Hoy says the same with “their desires for vengeance.” New Jerusalem Bible says still more generally “their malice.”

Their devices against me: devices translates a word meaning “plans, schemes, plots.” Such devices are secretive and have harmful consequences. The same word is used in Job 5.12; Isaiah 65.2; Jeremiah 6.19. In some cases this expression may be rendered, for example, “You know all their secret plans to harm me” or “You know all their secret plans to get revenge and to harm me.”

Quoted with permission from Reyburn, William D. A Handbook on Lamentations. (UBS Helps for Translators). New York: UBS, 1992. For this and other handbooks for translators see here .