(Mishnah): The following cases require three judges - monetary, theft and wounds, damage, half damage, double payment (of a thief) and payment of four or five (if a thief slaughtered or sold the kosher animal he stole).

(R. Meir): Rape or seduction of a virgin Na'arah (a girl within six months of becoming Bas Mitzvah) and Motzi Shem Ra (one who claimed that his bride had not been a virgin) require three judges.

(Chachamim): Motzi Shem Ra requires 23 judges as it can involve life and death. (If through the testimony of witnesses, the girl is found guilty of adultery, she will be given the death penalty).

(Gemara) - question: What is the source that monetary cases require three judges?

Answer: The pasuk states (Bamidbar 35:29), "And these will be to you an eternal law'' - I would have said that both monetary cases and capital cases require questioning and cross-examining of the witnesses; but where is the source that monetary cases actually require three judges?

(R. Yashiyah): The pasuk states (Shemos 22:7), "And the homeowner will approach the judges'' - this includes one judge; the next pasuk says "will come to the judges'' - this includes a second judge; that pasuk later says "whoever the judges will find guilty'' - that makes three judges.

(R. Yonasan): The first mentioning of a word (judges) can never be expounded (as it is needed for its context); rather, "will come to the judges'' includes one judge; "whoever the judges will find guilty'' includes a second judge; a Beis Din may never have an even number of judges, so they add one, which totals three.

(Rebbi): The phrase "whoever the judges will find guilty'' refers to two. But perhaps it means only one? The pasuk said "will approach the judges'' (it is written 'maleh' meaning with a letter Vav as the second last letter) - and since a Beis Din may never have an even number of judges, there must therefore be three.