And the Lord spake unto Moses and Aaron in the land of Egypt,.... Before they and the children of Israel came out of it, before the slaying of the firstborn, yea, before Moses came from the presence of Pharaoh, and had given him notice of it; and it is very probable even before the three days darkness, seeing it seems necessary it should be four days before the passover, since on the tenth day the lamb was to be taken, and on the fourteenth slain, Exo 12:3 and by what follows it looks as if it was at the beginning or first day of the month, and so the words may be rendered, "the Lord had spoke" (y); and the following account is deferred to this place, that there might be no interruption of the history of the plagues, and that the passover, with all its rites and ceremonies, both at the first institution and observance of it, and in later times, might be laid together. (y) "alloquutus antem fuerat", Junius & Tremellius, Piscator; "dixerat autem"; so some in Drusius, and Ainsworth.