John Trapp on Psalms 78:44

Verſ. 44. And had turned their rivers into bloud, &c.] Seven of thoſe Ten Plagues of Aegypt are here inſtanced, to aggravate the forgetneſs and perfidy of the Iſraelites. Good-turns aggravate unkindneſſes, and out offences are increaſed by our obligations.

And their flouds that they could not drink] Ʋſ que adeo ut aqua potabiles totam, alioqui ſtagnantem Aegyptum, deficerent. The Rabbines ſay (but who told them,Midras T[illegible: 1 letter] ling. I know not) that out of the ſame veſſel an Aegyptian drank bloud, and an Iſraelite water.