Who governeth the world with the palm of his hand, and all things obey his will: for he is the King of all, by his power dividing holy things among them from profane.
And in very deed for this cause have I raised thee up, for to shew in thee my power; and that my name may be declared throughout all the earth.
Breakdown
Pharaoh had no choice in the matter: it was of the LORD that he did not let the children of Israel go, until the LORD had enough justification to destroy Pharaoh and Egypt. All this was done to show the power of the LORD and to reverence his name.