R. Yossi Haglili says: Whence is it derived that the Egyptians were smitten in Egypt with ten plagues, and at the sea with fifty plagues? Of Egypt what is written? (Exodus 8:15) "And the necromancers said to Pharaoh: It is the finger of G–d, etc." And of the sea what is written? (Ibid. 14:31) "And Israel saw the great hand, etc." How many plagues by the finger? Ten. Say, then, that in Egypt they were smitten with ten plagues and at the sea with fifty.