Exodus 9

After the plague of boils Moses informs Pharaoh just who the God of Israel is. In 9:15 God declares that he has the power over Pharaoh's life but has chosen to spare him. Then in 9:16 God reveals why the king of Egypt has been spared: to glorify the God of Israel. The next verse brings a rebuke to Pharaoh; in spite of God's sovereignty Israel has not been sent out. But God declares that even Pharaoh's arrogance is being used to display God's power. So if God can use the stubborn defiance of an ancient king to advance his plan we need to consider what he can do with the repentant hearts of believers.
Stuart