which they had prepared

Ex12 details directions for the initial Passover feast. v11 caught my eye in describing how it is the Israelites were to eat that meal -- "with your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it in haste". The command here is to eat it not only dressed as if about to leave the house, but also quickly. It brings to mind the stereotype of an American man grabbing a bagel on the way out the door, briefcase in one hand, quick kiss to the wife and a dash to the car.

Why a meal in this manner? The rest of v11 and then v12 give you the Lord's reasoning -- "it is the LORD'S Passover. For I will go through the land of Egypt on that night, and will strike down all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgments--I am the LORD."

The Lord states that the reason for their hasty, dressed meal is because the Lord is executing judgment. The clear message is that God's people need always be on the ready for His judgment. Wonderful foreshadowing to Christ's later commands to be at the ready for His coming because we know not the time nor hour.

Yet another reason for a third consecutive post after such time away -- discipline = readiness.