Then the Lord said to Moses, "Pharoah's heart is hardened; he refuses to let the people go.
15 Go to Pharoah in the morning, as he is going out to the water; stand by at the river bank to meet him, and take in your hand the staff that was turned into a snake.
16 Say to him 'The Lord, the God of the Hebrews, sent me to you to say, "Let my people go, so that they may worship me in the wilderness." But until now you have not listened.'
17 Thus says the Lord, "By this you shall know that I am the Lord." See, with the staff that is in my hand I will strike the water that is in the Nile, and it shall be turned to blood…'
from Avivah Zornberg, p.99
Pharoah as impassive, enigmatic, represents a certain Egyptian ideal: the Sphinx, inexpressive, above human discourse. Ramban detects in this persona the effects of fear. In a similar vein, Rashi quotes the bizarre midrash about Pharoah's early-morning expeditions to the river:
"Look, he goes out to the water" (7:15) — to perform his bodily needs. For he would make himself into a god, claiming that he had no bodily needs (lit., "did not need to clear his bowels"); he would rise early in the morning, and go out to the Nile to perform his needs there."
Pharoah constructs himself as a god, without needs. … he takes in nothing and evacuates nothing. He neither eats nor eliminates waste matter, That cycle, depending on a vital traffic through the orifices of the body, is denied by one who claims to be beyond change, beyond the cycles of in and out, hunger and fullness, the vicissitudes of time and bodily state.
Avivah Zornberg 2001 The Particulars of Rapture: Reflections on Exodus Image/Doubleday New York