There are many differences between how the first Pesach was celebrated in Egypt, right before the exodus and how we celebrate Pesach today.
In Egypt, God instructed Moshe (Shmot 12:3,6-8, 10-11) “Speak to the entire community of Israel saying, ‘On the tenth day of this month they shall take- each man shall take a lamb for his family, a lamb for each household…You shall hold it in safekeeping until the fourteenth day of this month, they shall slaughter it- the entire community of Israel- between evenings (in the afternoon). They shall take of its blood and place it on the side of the doorposts and on the lintel of the houses in which they will eat the lamb. They shall eat the meat during the night. It shall be roasted over fire. They shall eat it with matzah and bitter herbs… You must not leave any of it over until morning. Any of it left over until morning must be burned in fire. This is how you must eat it: with your waist belted, your shoes on your feet and your staff in your hand. You must eat it in haste, it is a Pesach offering to God.’”
A few mitzvoth that differed on the first Pesach:
- Taking the lamb into their homes four days before they were required to slaughter it.
- Putting blood on the doorpost
- Eating quickly as the Exodus was imminent
In addition, Sifri and Targum state that since the Torah prohibits an uncircumcised person from eating the Pesach offering (Shmot 12:48 “but no uncircumcised male may eat of it”) all of the men who had not yet had a brit mila needed to be circumcised beforehand. As it says in Yechezkel 16:6: “…and I said to you: ‘In your bloods, live!’ And I said to you: ‘In your bloods live.’”
According to Alshich, “They could not have circumcised themselves on the night of Pesach. On the contrary, they were bidden to take the lamb four days earlier in order to give them breathing space for several days to recover from the operation. They could not afford to be sick at the time of the exodus. Three days are needed to recover from circumcision. God therefore wanted them to perform the circumcision first and wait three days to recover and then leave Egypt…They therefore had to pick up the lamb first, circumcise themselves and wait three days and finally slaughter the Paschal lamb, quickly eat the sacrifice and escape from Egypt.”
After hearing what B’nei Yisrael had to do to prepare for the first Pesach, risking their lives by bringing the lamb which was the god of the Egyptians into their homes for four days, getting the men of all ages circumcised, slaughtering and preparing the lamb, putting the blood on the doorposts and then eating in a rush with one foot out the door makes our cleaning, shopping and cooking for Pesach seem like a piece of cake.