NOTES for Exo 11:1-10
Of all the Egyptian plagues, the last--the death of the firstborn--seems the cruelest and most unjust. Of course, a situation in which everyone suffers because of one person's choice, even one endowed with unlimited power, does not look just from either a human or a divine point of view. The problem, however, is that the fallen world is not just at all. Nature knows no justice; neither does a society that lives by laws very much like the laws of nature, the laws of the herd or the pack. And a society made up of fallen people lives exactly that way. In the natural world it often happens that a leader's mistake destroys the herd; the same thing happens among people when the mistake of a ruler endowed with power, who does not know God, destroys an entire nation.
It would seem that God has the power to prevent such a course of events, and that God, who wants good for humanity, certainly should have done so. That is true, of course, but with one reservation: they could have been prevented only if Pharaoh had acknowledged God's authority over him. In this respect the last plague is no different from all the others. The point here is not God's revenge on those who reject Him, but that without such acknowledgment a person simply cannot make use of the salvation God can give him. It is impossible to grasp the hand stretched out to you and push it away at the same time.
Meanwhile Pharaoh finally decided to do exactly that: to push it away, and to push it away roughly and harshly, threatening Moses with death if he appeared before him again (Ex 10:28). Every relationship with Moses, both as a man and as God's prophet, was broken off, and Moses himself confirmed it (Ex 10:29). Now Pharaoh had to meet the power of God in all its fullness, while God's love and mercy were completely hidden from him. For God, this choice of Pharaoh meant enormous possibilities for Egypt, lost forever (v. 9). What they were, and what miracles God might have revealed in that country, one can only guess.
For Pharaoh, an encounter with God's power had to become truly terrible, all the more because its blow fell not only on him personally, but also on all his subjects. Yet given the position Pharaoh had taken toward Moses and toward the God of Israel, this was the only way to carry out God's plan. Now the situation would unfold so that practically nothing would depend on Pharaoh's choice anymore, and the Egyptians' only thought would be the desire to be rid of Moses himself, his people, and his God, whose mercy Pharaoh had rejected, making Him for himself a truly fearsome God.