I will at this time send all my plagues upon thine heart. A very emphatic announcement. At this time contrasts the immediate future with the past, and tells Pharaoh that the hour of mild warnings and slight plagues is gone by.
Now he is to expect something far more terrible God will send all his plagues—every worst form of evil—in rapid succession; and will send them against his heart. Each will strike a blow on that perverse and obdurate heart—each will stir his nature to its inmost depths.
Conscience will wake up and insist on being heard. All the numerous brood of selfish fears and alarms will bestir themselves. He will tremble, and be amazed and perplexed. He will forego his pride and humble himself, and beg the Israelites to be gone, and even intreat that, ere they depart, the leaders whom he has so long opposed, will give him their blessing (Exodus 12:32).
That thou mayest know. Pharaoh was himself to be convinced that the Lord God of Israel was, at any rate, the greatest of all gods. He was not likely to desert at once and altogether the religion in which he had been brought up, or to regard its gods as nonexistent.
But he might be persuaded of one thing—that Jehovah was far above them. And this he practically acknowledges in Exodus 9:27 and Exodus 9:28.