וְיָדְע֤וּ מִצְרַ֙יִם֙ כִּֽי־אֲנִ֣י יְהוָ֔ה בִּנְטֹתִ֥י אֶת־יָדִ֖י עַל־מִצְרָ֑יִם וְהוֹצֵאתִ֥י אֶת־בְּנֵֽי־יִשְׂרָאֵ֖ל מִתּוֹכָֽם׃
Rashbam on Exodus
Egypt will know that I am ruler and master of the whole universe. This will include all the people who up until now had refused to acknowledge that there is such a G’d.