In the Beracha of "Ga’al Yisrael," which we recite at the very end of the "Maggid" section during the Seder, we express our wish to be able to offer the Pesah sacrifices and partake of them in the Bet Ha’mikdash: "Ve’nochal Sham Min Ha’zebahim U’min Ha’pesahim." Some versions of the Haggada text reverse the sequence of this phrase, and read, ""Ve’nochal Sham Min Ha’pesahim U’min Ha’zebahim." However, the clear consensus among the Halachic authorities is that one should recite, "Ve’nochal Sham Min Ha’zebahim U’min Ha’pesahim." The reason is that the term "Zebahim" refers to the Hagiga sacrifice, which was offered in conjunction with the Pesah sacrifice, and "Pesahim" obviously refers to the Pesah sacrifice. Halacha requires eating the meat of the Hagiga before partaking of the Pesah sacrifice, because the Pesah sacrifice must be eaten "Al Ha’soba" – in a state of satiation. Naturally, then, one should recite, "Ve’nochal Sham Min Ha’zebahim U’min Ha’pesahim," mentioning our anticipated eating of the Hagiga before our eating of the Pesah sacrifice.
There are, however, some Halachic authorities who make an exception when the Seder takes place on Mosa’eh Shabbat (as the second Seder does this year, 5775). Although the Pesah sacrifice is offered on Ereb Pesah even when Ereb Pesah falls on Shabbat, the Hagiga sacrifice is not offered in such a case, as it does not override the Shabbat prohibitions. Therefore, according to some Halachic authorities, when the Seder is observed on Mosa’eh Shabbat, we should first make mention of "Pesahim" – the Pesah sacrifice, which is clearly far more prominent in such a year, when the Hagiga is not offered at all.
The Kanhag (Kenesset Ha’gedola, work by Rav Haim Banbenishti, Turkey, 1603-1673), however, disagrees. In this Beracha, he explains, we are not speaking about this Pesah, but rather of our hopes of celebrating Pesah in the Bet Ha’mikdash in the future. The fact that Pesah happens to fall on Mosa’eh Shabbat this year certainly does not necessitate that this will happen next year, when we hope to be celebrating in the newly rebuilt Mikdash. Therefore, regardless of when Pesah falls out, the Kanhag rules, we should recite the text of "Ve’nochal Sham Min Ha’zebahim U’min Ha’pesahim." This is, indeed, the ruling that one should follow.
Summary: There is some controversy surrounding the precise text of the sentence, "Ve’nochal Sham Min Ha’zebahim U’min Ha’pesahim" in the Beracha of "Ga’al Yisrael" recited at the Seder. Nevertheless, it is proper to recite it this way – "Ve’nochal Sham Min Ha’zebahim U’min Ha’pesahim" – regardless of on which night of the week the Seder is observed.
