Moses Stretched Forth His Hand Toward Heaven and There Was a Thick

"And Moses stretched out his hand toward the heavens, and there was thick darkness in all the land of Egypt for three days" (Exodus 10:22). Our Rabbis, of blessed memory, said: there were seven days of darkness. How so? During the first three days, whoever was sitting and wished to stand could stand, and whoever was standing and wished to sit could sit. During the last three days, anyone who was sitting could not stand, and one who was standing could not sit, and one who was crouching could not straighten up. From where do we know this? For so it is written: "They did not see one another" (Exodus 10:23), that is three; "nor did anyone rise from his place for three days" (Exodus 10:23), that is six. And which is the seventh day? "And there was the cloud and the darkness... and it gave light" (Exodus 14:20). This is the day of the Sea. And likewise in Egypt the cloud gave light to Israel and brought darkness upon the Egyptians, as it is said: "They did not see one another" (Exodus 10:23). "But for all the children of Israel there was light" (Exodus 10:23): and it gave light to Israel and showed them all the vessels of silver and gold and garments and all the wealth of Egypt; and whatever was in chests and barrels and hidden treasures it showed them. And the Israelites would ask for them, and the Egyptians would give to them against their will, for the Israelites would say to them: There, in such and such a place, you have such and such a vessel. This is the meaning of "and there was thick darkness."