Parshas Vaeiyra opens with G-d assuring Moshe that He will redeem the Jewish People from Egypt and bring them into the Land of Israel. After the interjection of a detailed genealogy of the tribe of Levi (Moshe’s extend family), the parsha continues with G-d telling Moshe that Pharaoh will initially refuse to let the Jewish People go.

Moshe and Aaron appear before Pharaoh to request a three-day hiatus from work for the Jews to serve G-d in the desert. To prove the divinity of his message, Moshe miraculously turns his staff into a serpent. When the Egyptian sorcerers counter by transforming their own staffs into snakes, Moshe’s snake swallows up the other snakes. 

 Even so, Pharaoh refuses to let the Jewish People go, and the ten plagues begin. The first seven plagues - blood, frogs, lice, a swarm of wild beasts, pestilence, boils and hail - occur in this week's portion; each one lasts for a full week. Each plague defies the prevailing laws of nature to prove to Pharaoh that G-d means business and he should let the Jewish People leave.   Despite the terrible plagues, Pharaoh refuses to let the Jews go. At this point, his decision is irrational; as a punishment for all of his terrible deeds, G-d hardens Pharaoh's heart and does not allow him to free the Jews until all ten plagues had been visited upon the Egyptians.