Sanhedrin 3:2-3

Sanhedrin 3:2

If one litigant told the other, "My father is acceptable to me (as a judge),” “your father is acceptable to me” or “three cattle ranchers are acceptable to me,” Rabbi Meir says he may change his mind but the Sages say that he may not. If one litigant was required to take an oath and the other says, “Swear to me by the life of your head,” Rabbi Meir says he can change his mind (and still require the normal oath) but the Sages say that he may not change his mind (and must rely on the formula he himself called for).

Sanhedrin 3:3

The following are ineligible to serve as judges or witnesses: dice players, those who lend for interest, those who race pigeons, and those who deal in Sabbatical-year produce. Rabbi Shimon said they originally included those who collected Sabbatical-year produce (i.e., for their own use) but when tax collectors proliferated (placing heavy financial burdens on the people even in Sabbatical years), they only disqualified those who deal in Sabbatical-year produce. Rabbi Yehuda said that these disqualifications only apply to those who have no other profession but if they have another profession, they are still eligible.