Moses and Aaron repeatedly come before Pharaoh to demand in the name of G-d, "Let My people go, so that they may serve Me in the wilderness." Pharaoh repeatedly refuses. Aaron's staff turns into a snake and swallows the magic sticks of the Egyptian sorcerers.
Pharaoh still refuses to let the Jews go. Moses warns him that G-d will smite Egypt. Pharaoh remains impervious. G-d begins to send a series of plagues upon the Egyptians. In the throes of each plague, Pharaoh promises to let the Children of Israel go; but he reneges the moment the affliction is removed.
1) Aaron strikes the Nile, the waters turn to blood;
2) Swarms of frogs overrun the land;
3) Lice infest all men and beasts. Still, Pharaoh remains stubborn;
4) Hordes of wild animals invade the cities,
5) a pestilence kills the domestic animals,
6) painful boils afflict the Egyptians.
7) Fire and ice combine to descend from the skies as a devastating hail. Still, "the heart of Pharaoh was hardened and he would not let the children of Israel go; as G-d had said to Moses."
The people of Egypt have suffered too much. They beg Pharaoh to let the Jews go. When Moses comes to warn Pharaoh of the eighth plague, Pharaoh says: You say that you want to go serve your G-d? I'll let the men go, as long as the women and children stay behind. No, says Moses, we must all go, men women and children, cattle and herds. Pharaoh once again refuses.
The next plagues descends upon Egypt.
8) a swarm of locusts devours all the crops and greenery;
9) a thick, palpable darkness envelops the land.
The Israelites are instructed to bring a "Passover offering" to G-d: a lamb or kid is to be slaughtered and its blood sprinkled on the doorposts and lintel of every Israelite home, so that G-d should pass over these homes when He comes to kill the Egyptian firstborn. The roasted meat of the offering is to be eaten that night together with matzah (unleavened bread) and bitter herbs.
Then G-d brings the tenth plague upon Egypt,
10) all the firstborn of Egypt are killed at the stroke of midnight of the 15th of the month of Nissan.