John Trapp on Psalms 109:16

Verſ. 16. Becauſe that he remembred not to ſhow mercy] Here the Prophet beginneth to ſhew why he uſeth ſuch doleful imprecations againſt his enemies, viz. not out of a ſpirit of revenge, or a falſe zeal, but as truly ſeeking Gods glory, and his Churches ſafety, which could not other wiſe be procured, unleſs theſe mercileſs men were devoted to deſtruction. He remembred not, that is, de industria oblitus eſt & omiſit, he forgot and neglected it for the nonce.