Pesachim 86B

יכול יהא נאכל בשתי חבורות, תלמוד לומר: ״בבית אחד יאכל״.

I might have thought that a single Paschal lamb may be eaten in two separate groups; therefore, the verse states: “In one house should it be eaten.”

במאי קמיפלגי? רבי יהודה סבר: יש אם למסורת. ורבי שמעון סבר: יש אם למקרא.

The Talmud asks: With regard to what principle do they disagree? The Talmud answers: R' Yehuda holds that the consonantal text of the Torah is authoritative; meaning, the primary understanding of the verse is according to the way it is spelled. If this is the case, the verse may be rendered: In one house should he eat it [yokhal], referring to the person eating the Paschal lamb. This would indicate that one eating from the Paschal lamb must eat in one location, but the verse does not prohibit dividing the offering between multiple groups. And R' Shimon holds that the vocalized text of the Torah is authoritative. Since the word is pronounced ye’akhel, it is clear that it is referring to the Paschal lamb itself, and the verse requires that the offering be consumed by a single group of people (Rabbeinu Ḥananel).

היו יושבין ונפרסה מחיצה ביניהם, לדברי האומר פסח נאכל בשתי חבורות ⁠— אוכלין, לדברי האומר אין הפסח נאכל בשתי חבורות ⁠— אין אוכלין.

The Talmud attempts to clarify this halakha: If members of a group were sitting and eating the Paschal lamb, and a partition was spread between them such that they now constitute two separate groups, according to R' Yehuda, who says a Paschal lamb may be eaten in two groups, they may continue to eat; according to R' Shimon, who says a Paschal lamb may not be eaten in two groups, they may not continue to eat because they now constitute two groups.