Behold, regarding the reason for the plagues, Hashem said that they were so that Egypt would know that "I am Hashem" (Exodus 7:5). At first glance, is it worth disrupting the natural order with signs and wonders just so the Egyptians would come to faith? It can be said, if you examine closely, it does not say "so that the Egyptians would know that I am Hashem," but rather "and Egypt will know that I am Hashem." This refers to the spiritual impurity (klipah) of Egypt, which is denial, as Pharaoh said (Exodus 5:2): "I do not know Hashem." However, in truth, Pharaoh did not deny the existence of Hashem and that He is the Creator, as Ramban wrote (ibid, 3): "Behold, Pharaoh was a great wise man, and he knew of God and acknowledged Him, as he or his predecessor said to Joseph, 'after God has made all this known to you' (Genesis 41:39). 'A man in whom is the spirit of God' (ibid, 38). But he did not know the specific name, and thus responded, 'I do not know Hashem'." Meaning, Pharaoh thought that Hashem had abandoned the management to the forces of nature and does not supervise the lowly, and therefore he said: "Who is Hashem that I should obey His voice" (Exodus 5:2), implying that He does not govern and oversee this world. According to this, when he said 'I do not know Hashem,' the meaning of 'knowing' is in the sense of connection (see Genesis 4:1), meaning, "I have no connection with Him."