Chasidut zu Schemot 7:23

Exodus 7,23. “Pharaoh turned and went to ‎his palace and did not pay attention even to this.” ‎Our sages, analyzing the word: ‎לזאת‎, “to this,” cite ‎Leviticus 16,3 where the Torah introduces the Temple ‎service of the High Priest on the Day of Atonement, ‎with the words: ‎בזאת יבא אהרן אל הקודש‎, “equipped with ‎this Aaron is to enter the Sanctuary, etc;” as an allusion ‎to the collective soul of the Jewish people. We must ‎always remember that the universe was created only ‎for the sake, or on account of, the Jewish people (and ‎their destiny on earth). In other words, the word ‎זאת‎ ‎refers to the principal component of something. We ‎find this repeated when Moses blesses the Jewish ‎people for the last time before dying, in Deuteronomy ‎‎33,1 when the Torah writes: ‎וזאת הברכה אשר ברך משה וגו'‏‎, ‎‎”and this is the blessing which Moses invoked, etc.” ‎When Moses, on the occasion of the first plague visited ‎upon the Egyptians uses the word ‎זאת‎, he does so to ‎bring home to Pharaoh the idea that the Jewish people ‎are the principal reason that the universe exists as it ‎does. It was this that Pharaoh refused to believe and ‎that is why he chose to ignore the plague.‎