"About midnight I will go throughout Egypt. Every firstborn son in Egypt will die." (Exodus 11:4-5)
God tells Moses that he will bring one more plague on Pharaoh and Egypt, after which Pharaoh will let them go. He instructs the Israelites to ask their Egyptian neighbours for articles of silver and gold. God has made the Egyptians favourably disposed toward the Israelites, and the Israelites plunder Egypt without violence. Moses tells Pharaoh: About midnight I will go throughout Egypt. Every firstborn son in Egypt will die, from the firstborn son of Pharaoh who sits on the throne to the firstborn son of the female slave, who is at her hand mill, and all the firstborn of the cattle as well. There will be loud wailing throughout Egypt. Then all Pharaoh's officials will bow down to Moses and beg him to go. And Moses, hot with anger, leaves Pharaoh.
The tenth plague is the most severe and the most theologically weighty. It is the death of the firstborn that will finally break Pharaoh's resistance, and it is the death of the firstborn that will be commemorated forever in the Passover. The Catechism identifies this plague as the most direct foreshadowing of the Cross: just as the firstborn of Egypt die, the eternal firstborn Son of God will die so that the people of God may live (CCC 1364). The death that falls on Egypt is the death that Christ will take upon himself, so that the destroying angel will pass over all who are covered by his blood.
Brothers and sisters, the tenth plague is a dark night before a new dawn. The wailing of Egypt at midnight is the darkness before the Exodus morning. Every great deliverance in the story of God follows this pattern: the worst darkness is immediately before the light. If you are in the midnight of your own Egypt, the dawn is closer than it seems.
Lord God, you announced the final plague to Pharaoh through Moses and nothing could stop it. You are the Lord of history, and every night of darkness serves the morning of deliverance you are preparing. Come, Lord, and bring us through the midnight to the Exodus. Through Christ our Lord. Amen.