Must it be eaten with matza and marror?
Must it be eaten with a pre-designated group?
Must it be eaten only on the evening of the 15^th?

Despite its uniqueness, though, in certain ways it is most similar to the korban Todah. In the following shiur, we discuss these similarities in order to better understand the laws of Pesach.

Introduction
In Parshat Tzav (see 7:11-18) we learn that the korban Shlamim can be offered in two manners:

a) As a Todah - a thanksgiving offering - which can be eaten only on that day and evening and must be eaten with forty 'rolls and pitah' [thirty baked matza and ten baked chametz];
b) As a standard neder or nedava - to fulfill a vow - which can be eaten that day and the next day [and there is no requirement to eat it with bread].

Even though the Shlamim is a korban nedava - a voluntary offering - there are four instances when an individual is obligated to offer a korban Todah. This obligation is based on Tehillim chapter 107, which describes four examples of an individual's redemption from danger. [These are the same four instances when one is required today to "bentch gomel" - i.e. one who crosses a desert, travels the sea, recovers from illness, or is released from prison. See Tehillim 107.]

In comparison to other korbanot, the korban Pesach [itself yet another category of "kodashim kalim"] is most similar to the korban Todah, for two reasons:

1) It cannot be eaten the next day, i.e. one must finish eating the korban by dawn [or according to some opinions by midnight].
2) It must be eaten together with bread. The Todah is eaten with matza and chametz bread, whereas the Pesach is eaten only with matza bread.

Thanksgiving - In Public
Let's consider a typical case, for example - someone was gravely ill and recovers and decides to offer a korban Todah. He brings his animal to the Bet HaMikdash together with 40 loaves of bread. After the owner gives the required "chazeh v'shok" and 4 loaves to the kohen, he is left with an enormous amount of meat and bread that must be eaten on that day (or at the latest - that night) in Jerusalem. Obviously, one person could not each so much meat and bread by himself. Instead, he would have to share it with others. Thus, the special laws of the korban Todah create a situation where the owner must invite a groups of friends and possibly even strangers to join him for what we would call today a barbecue. Usually, whenever people sit down to eat (especially when there is bread and meat), they also sit down and talk. What will they talk about?

Inevitably, the people invited would ask the owner: 'What happened? Why are you offering a korban Todah?' [Just like in shul, when someone 'bentches gomel' - everyone asks 'what happened?'] The owner would then explain to his guests that he had been sick and 'baruch Hashem' he is now better, etc., thus praising God in public, and properly fulfilling the ultimate purpose of the korban Todah! In other words, the special laws of the korban Todah help create an environment through which its purpose will be best fulfilled.

[It is significant as well that to properly praise God it is not sufficient to simply thank Him privately in tefilla, but it is also important to thank Him in public. In many ways, these laws relate to the social nature of man and his need to discuss and share his experiences with others.]

The Korban Todah of a Nation
The special laws of the korban Pesach can be understood in a similar manner, for it too is an offering of thanksgiving - not for a personal case of redemption, but rather for our national redemption.

Let's review the special laws of the korban Pesach to show how they help to create a special environment in which we can thank God. [If you are not familiar with these laws, see mishnayot Mesechet Pesachim chapter 5.]

a) First of all, in the time of the Bet HaMikdash, everyone was obligated to gather in Jerusalem and offer their korbanot in the Bet HaMikdash while the Leviim sang the Hallel. [That in itself is a 'national thanksgiving.']

b) Eating the korban Pesach was by 'invitation only.' In other words, it was necessary to know ahead of time (before the korban is offered) who would be eating it. The purpose of this law is not to limit the amount of participants, but rather to make sure that everyone will attend [just like invitations for a wedding etc.]!

c) The korban must be eaten with matzot and marror. The primary reason for eating the korban Pesach with matza is similar to the reason for eating the korban Todah with matza; that is, to ensure that everyone 'sits down' to a meal. [However, once we must eat bread, the Torah chooses the type of bread most appropriate for the occasion - matza and not chametz - to remind us of our slavery in Egypt.]

[Note that the primary reason for eating matza with the korban Pesach cannot be because of our rush when we left Egypt (see Shmot 12:34-39), for this original mitzvah was given on Rosh Chodesh Nisan, before we even left Egypt (see Shmot 12:1-8)! The matza we baked on the day after we left Egypt explains the reason for the seven days of Chag HaMatzot (see Shmot 13:2-9), through which we are to remember 'leaving Egypt,' but the matza that we eat with the korban Pesach is for an independent reason! (See Rambam Chametz u'Matza 6:1).]

d) Marror can be explained in a similar manner. Its primary purpose is to make the meal of the korban Pesach more 'formal' (and tasty - a little 'salad with the shawarma'), but once we are adding herbs to our 'sandwich,' we take a bitter herb to remind us of our affliction in Egypt [l'havdil - sort of like food at a 'theme party']. (This may also explain why Romaine lettuce is preferable for marror over horseradish.)

e) Using only roasted meat, not cooked but not raw (see 12:9-10) also ensures that it will be an enjoyable meal for all.

f) No leftovers - ensures that everyone will enjoy the meal and not think about 'saving' the meat for later.

Today, even though we are unable to offer the korban Pesach, we accomplish the same goal at the seder. Our custom of sitting down to a festive meal with family and guests while reading the haggadah, telling its story and singing its songs, achieves this same goal. May we be "zocheh" to fulfill it 'next year in Jerusalem.'

Chag Kasher V'samayach,
    Menachem

For Further Iyun
1. Read Tehillim 107. Note how its opening and closing verses focus on national redemption in addition to the four examples of individual redemption described in the main part of the mizmor. Note also how most of those cases also relate in some manner to the events of Yetziat Mitzraim ["yordei ha'yam," "holchey midbar," etc.) Relate this to the above shiur.

2. As we say in the Haggada section of "v'hi sh'amda l'avoteinu... sheb'chol dor v'dor omdim aleinu l'chaloteinu...," our national redemption was not only a 'one-time' historical event; rather, in every generation situation arise when we are in need of national redemption. As usual, relate this to the above shiur.