The passage describes the ritual observance of the Passover feast as commanded by God to the Israelites before their exodus from Egypt. It details how they were to select an unblemished lamb on the 10th day of the month and slaughter it at twilight on the 14th day. They were to smear its blood on their doorposts and eat the meat that night while dressed for travel. This was to serve as a memorial meal commemorating God delivering them from bondage in Egypt when he struck down the firstborn of Egypt but passed over Israelite houses with lamb's blood on their doors.