Aharon A. Fischman
After we read the entire story of Yetziat Mitzrayim , we conclude with - "Every person must view himself as if he personally had left Egypt." This ideal is the driving force behind a majority of the seder narrative, including the axiom that affects us today, "Had Hashem not redeemed our ancestors from Egypt when He did, we would certainly still be Pharoah's slaves.
It is with good reason that we must give praise and thanks to Hashem for our personal redemption. The Haggadah concludes - Since each of us must see ourselves as leaving Egypt, therefore we are obligated to give thanks and praise to Hashem. It would seem logical to give thanks to Hashem with the recitation of Az Yashir, the song in which we praise Hashem directly in the first person, for the miracle of the yitziah. However, instead of using this selection from the Torah, the Haggadah continues with the beginning of the standard Hallel which is said on every holiday. Why do we say Hallel instead of the more obvious Shirat HaYam?
On the surface, the answer seems clear. The Hallel continues with "As bnei Yisrael left Egypt, the House of Jacob from a nation which spoke a foreign language...the sea saw bnei Yisrael and fled". This paragraph of Tehillim refers to the miracle of Yetziat Mitzrayim and the miracles at the Sea of Reeds. Since we say Hallel for special occasions such as Pesach, placing it in the seder would be a logical selection in that it includes the first person perspective of praise of Hashem, and the story of the yetziah.
However, upon further examination, the paragraphs of Hallel in the Magid section do not highlight the miracles specifically associated with the Yam Suf and the yetziah, rather, they seem to glorify Hashem in general. For example, in the same pasuk that describes the splitting of Yam Suf, the splitting of the Jordan River is also mentioned - 'HaYardain Yesov L'Achor'. While the crossing of the Jordan is significant in our history, it has little to do with the recounting of Yetziat Mitzrayim. Clearly it would make more sense for the Haggadah to use Shirat HaYam as a direct means of praising Hashem for the yetziah instead of the two paragraphs of Hallel which only seem to make a cursory reference to the yetziah and Yam Suf.
To answer this question, it is necessary to look at the source for saying Hallel at the seder. According to Rabbi Eliezer (Pesachim 117a), the prophets amongst bnei Yisrael sang these paragraphs of Hallel while walking through the Yam Suf. Only upon emerging from the sea did all of bnei Yisrael sing the Shirat HaYam. It is evident that this opinion views Hallel as a similar praise to that of Shirat HaYam since both of these selections have their roots in the miracles of Yetziat Mitzrayim. However, given that both praises of Hashem come from the same origin, why is one selected over the other?
A possible answer may be found in the root of the mitzvah of Sippur Yetziat Mitzrayim itself. As mentioned above, 'every person must see himself as if he himself left Egypt'. The Shirat HaYam that bnei Yisrael sang after emerging from the sea was a miracle in its own right, since all of bnei Yisrael either sang in unison, or repeated the chorus spontaneously. Hallel, by contrast, is recited on most holidays or at any time that an individual experiences a personal salvation. Those of us sitting at the seder table would have a hard time expressing thanks to Hashem for Yetziat Mitzrayim in the terms of the Shirat HaYam. The supernatural circumstances surrounding it do not capture our ability to express thanks on the level of 'tevah' (natural existence), in which we exist. Hallel, on the other hand, is a form of Shirah familiar to us, and we use it to express gratitude and thanks on a regular basis for more ordinary incidents of salvation. In order for us to give thanks to Hashem at the Seder Table as if we had just left Egypt, we use a Tefillah that we can understand from our own experiences. While the Shirat HaYam was elegant and tremendous in its power and praise, it cannot accurately portray how we feel when we left Egypt; it is beyond our comprehension of day to day events and history. Hallel, on the other hand, serves as our personal praise of Hashem for redeeming us from Mitzrayim many years ago.