In preparation for the coming of the last plague, the LORD gave explicit instructions to Moses and Aaron about how to commemorate their deliverance by their LORD.
Verses 21 – 28 record what Moses did after receiving the description of what the LORD was about to do.
Verses 29-36 relate the coming of the tenth plague and its immediate aftermath. The time for judgment (on Egypt) and deliverance (for Israel) had come.
Verses 37 – 41 summarize the exit from Egypt. Verse 37 itself is a turning point in the book of Exodus.
Verses 43 – 51 contain more details about how and who could celebrate Passover. It was probably necessary to add these rules because so many non-Hebrews exited Egypt when they did.
The book of Exodus is the second book of the Torah (“law”). It continues the story of Genesis concerning the migration of the family of Jacob (the Israelites) to Egypt (Genesis 50). It describes the commissioning of Moses and Aaron as God’s representatives on earth to accomplish God’s deliverance of His people from slavery in Egypt and lead them to the Promised Land (the land of Canaan). It also relates the miraculous deliverance from Egypt beginning with the plagues on Egypt and the crossing of the Red Sea. It then describes the journey to Mount Sinai and the establishment of the Mosaic covenant with the Israelites. The last part of the book involves the specifications and building of the tabernacle – the place where the Lord Himself dwelt amongst His people.
In the book of Exodus, the focus shifts to the deliverance of God’s people.
Chapter 12 continues the narrative of the tenth and final plague on Egypt – the death of the firstborn. It includes instructions about what was necessary to celebrate a new ritual called Passover and a feast involving unleavened bread. It also has the account of the plague itself, which describes the LORD going through Egypt and the death of all the firstborn except those in households with blood on the doorposts. Pharaoh finally allowed the Israelites and their livestock to leave Egypt. The chapter ends with more instructions concerning the celebration of Passover.
Chapter 12 can be outlined as follows: