Psalm 135:8

Verse 8. Who smote the firstborn of Egypt. The first born only were smitten; these were singled out in every family with unerring precision, the houses of the Israelites, wherever the blood of the lamb was sprinkled on the door posts, being passed over. The death of all those thousands, both of man and beast, took place at the same instant -- "at midnight."

Is God unrighteous, then, that taketh vengeance? No; this is an act of retribution. The Egyptians had slain the children of the Israelites, casting their infants into the river. Now the affliction is turned upon themselves; the delight of their eyes is taken from them; all their firstborn are dead, from the firstborn of Pharaoh that sat upon his throne, unto the firstborn of the captive that was in the dungeon. --Thomas S. Millington, in "Signs and Wonders in the Land of Ham", 1873.

Verse 8. And beast. The Egyptians worshipped many animals, and when the firstborn of the sacred animals died the circumstance greatly increased the impressiveness of the plague as an assault upon the gods of Egypt. --C. H. S. Suggested by Otto Von Gerlach.

Verse 8-12. Worthy is Jahve to be praised, for he is the Redeemer out of Egypt. Worthy is he to be praised, for he is the Conqueror of the Land of Promise. --Franz Delitzsch.