וַאֲנִ֗י הִנְנִ֤י מְחַזֵּק֙ אֶת־לֵ֣ב מִצְרַ֔יִם וְיָבֹ֖אוּ אַחֲרֵיהֶ֑ם וְאִכָּבְדָ֤ה בְּפַרְעֹה֙ וּבְכָל־חֵיל֔וֹ בְּרִכְבּ֖וֹ וּבְפָרָשָֽׁיו׃
«至於我，看哪，我要使埃及人的心剛硬，他們就必跟在以色列人後面進去；我要在法老和他的全軍、他的戰車和馬兵身上得榮耀。»
Or HaChaim
ואני הנני מחזק את לב מצרים, "And I, behold I will harden the heart of Egypt, etc." G'd's attribute of Mercy informed the Israelites from a sense of compassion that they should not be worried when they saw that the sea did not close after they had crossed, but remained open for the Egyptian cavalry to descend into in hot pursuit. He explained that this was only the preamble of G'd dealing with the entire Egyptian army and wiping them out.