And you shall know that I am Hashem. — Shemos 10:2

Did the first seven plagues not cause them to know? Here we learn that to “know Hashem” is an unending effort which should be continued always, because His greatness is endless. Thus Moshe requested, after Hashem had revealed Himself so abundantly to Moshe, “let me know You.”~ R’ Avigdor Miller zt”l