Classical material not listed by Torah Temimah under this passuk (EXTRA).
Core Text — EXTRA
וַיֶּֽחֱזַק֙ לֵ֣ב פַּרְעֹ֔ה וְלֹ֥א שָׁמַ֖ע אֲלֵהֶ֑ם כַּאֲשֶׁ֖ר דִּבֶּ֥ר יְהֹוָֽה׃ {ס}
English: “And Pharaoh’s heart was strengthened” — \ldots of his own accord.