Midrasz do Wyjścia 13:15

(Exod. 13:17:) NOW IT CAME TO PASS, WHEN PHARAOH HAD LET <THE PEOPLE> GO…. This text is related (to Job 9:4): ONE WISE OF HEART AND MIGHTY IN STRENGTH—WHO HAS HARDENED HIMSELF AGAINST HIM AND PROSPERED? [ONE WISE OF HEART:] This is the Holy One, as stated (in Job 12:13): WITH HIM ARE WISDOM AND {UNDERSTANDING} [VALOR]. (Job 9:4, cont.:) WHO HAS HARDENED HIMSELF AGAINST HIM AND PROSPERED? The generation of the flood hardened themselves against him; so he washed them away with water. The generation of the dispersion hardened themselves against him; <so> he dispersed them throughout the world. The people of Sodom hardened themselves against him, and what was their end? (Gen. 19:24:) THEN THE LORD RAINED DOWN UPON SODOM <… BRIMSTONE AND FIRE.> (Exod. 5:2:) PHARAOH SAID: WHO IS THE LORD? For the Holy One had said to him (in vs. 1): LET MY PEOPLE GO; but he also hardened himself, as stated (in Exod. 13:15): AND IT CAME TO PASS, WHEN PHARAOH HARDENED HIMSELF AGAINST LETTING {THEM} [US] GO. As soon as the plague of the first-born came upon him, he immediately let them go. It is therefore stated (in Exod. 13:17): NOW IT CAME TO PASS, WHEN PHARAOH HAD LET < THE PEOPLE > GO….

And it shall be when thy son asketh thee tomorrow: “What is this?” (Exod. 13:14). Sometimes tomorrow means the next day, and sometimes it means the time to come. In the verse When thy son asketh thee tomorrow saying: “What is this?”, tomorrow means in the time to come. But the verse Tomorrow shall this sign be (Exod. 8:19) actually refers to the next day. In the verse Tomorrow will I stand upon the top of the hill (ibid. 17:9), tomorrow refers to the next day, but the verse Tomorrow your children might speak unto our children (Josh. 23:24) refers to the time to come. What is this? This refers to the laws of Passover. And it came to pass, when Pharaoh would hardly let us go (Exod. 13:15). One might understand this to mean that he became hardened of his own accord, therefore Scripture says: And the Lord hardened the heart of Pharaoh (ibid. 9:12). That the Lord slew all the firstborn (ibid. 13:15). From this they taught: The firstlings of cattle are sacrificed because of what happened to the firstborn men in Egypt, and the firstborn of man is redeemed because of what happened to the firstborn of cattle in Egypt.