For the scripture says unto Pharaoh,
Even for this same purpose have I raised you up, that I might show my power in you, and that my name might be declared throughout all the earth.
All Commentaries on Romans 9:17 Go To Romans 9
John Chrysostom
AD 407
God endured Pharaoh for long time in the hope that he might repent, but even when he did not do so God was patient with him in order to display his own goodness and power, even if Pharaoh gained nothing from it.