John Calvin Commentary Exodus 9:13

"And Jehovah said unto Moses, Rise up early in the morning, and stand before Pharaoh, and say unto him, Thus saith Jehovah, the God of the Hebrews, Let my people go, that they may serve me." — Exodus 9:13 (ASV)

And the Lord said unto Moses, Rise up. God returns again to threats, to try the mind of the wicked king; not that there is any hope of a cure, but that his obstinacy may be more and more discovered. For it was desirable as an example, that it should be known openly how madly those, who are cast into a reprobate state of feeling, and who are possessed by a spirit of willfulness, rush upon their own destruction.

Surely it would be incredible that any human being should have ever resisted God with such headstrong folly and obstinacy, unless this picture had been presented to us. How often was Pharaoh commanded to send the people away, and on every occasion a ratification of the command¹⁰⁷ was added!

So that God no less thundered from heaven than He spoke on earth by the mouth of His servant and ambassador; yet still the mind of the tyrant was not subdued into obedience, because Satan alienates the minds of those whom, by God’s permission, he holds in devotion and bondage to himself. Meanwhile, they heap up more terrible vengeance against themselves by their impious contempt of warnings.

¹⁰⁷ The French Version supplies “avec menaces;” with threatenings.