"If three have eaten at one table and they have spoken no words of Torah over it, it is as if they have eaten of idolatrous sacrifices..." (Avot 3:3)

A dead person may be reincarnated into an animal that will serve as food for humans….

Woe to sons who have banished from the table of their father! In the name of the Maggid of Mezritch, I heard an account of the way in which the Baal Shem Tov explained this text, which declares that it is as though these three ate of sacrifices to dead idols. The Hebrew, though, means literally, "as though they ate of the sacrifices of the dead." The esoteric meaning is that a dead person may be reincarnated into an animal that will serve as food for humans, in order that they should say words of Torah over it at their meal table - and through this, the dead person who was reincarnated will be given new life in the heavenly realm. But if no words of Torah are said, the dead person reincarnated into the source of that food is simply "sacrificed" and cast off to remain an inanimate entity.

This is why the text speaks of "the sacrifices of the dead". And this is why we find in the Talmud (Berachot 3a): "Woe to sons who have banished from the table"; Who have they banished? "Their father"! For it is possible that it was the father of the man who is dining, that was reincarnated into the creature that provided the food…

[Be'er Mayin Chaim on the Passover Haggada; L'shon Chassidim; Midrash Rivash Tov (5); Sefer Baal Shem Tov]