Shemot 10:20-22

Orthodox Jewish Bible

²⁰ But Hashem hardened lev Pharaoh, so that he would not let the Bnei Yisroel go.

²¹ And Hashem said unto Moshe, Stretch out thine yad toward Shomayim, that there may be choshech over Eretz Mitzrayim, even choshech which he can feel.

²² And Moshe stretched forth his yad toward Shomayim; and there was a thick choshech in kol Eretz Mitzrayim shloshet yamim;