ויהי בשלח פרעה וגו' (שמות יג יז). זש"ה חכם לבב ואמיץ כח מי הקשה אליו וישלם (איוב ט ד), [חכם לב], זה הקב"ה, שנאמר עמו חכמה (ותושיה) [וגבורה] וגו' (שם יב יג), מי הקשה אליו וישלם, דור המבול נתקשו כנגדו ושטפן במים, דור הפלגה נתקשו כנגדו, הפיצם בכל העלם, אנשי סדום נתקשו כנגדו, מה היה סופן, וה' המטיר על סדום (בראשית יט כד), פרעה אמר מי ה' (שמות ה' ב), והקב"ה אמר לו שלח את עמי (שם שם א), ואף הוא נתקשה, שנאמר ויהי כי הקשה פרעה (לשלחם) [לשלחנו] (שם יג טו), כיון שבאת מכת הבכורות עליו, מיד שלחן, לכך נאמר ויהי בשלח פרעה וגו'. (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….