Sanhedrin 3:4-5

Sanhedrin 3:4

The following are the ineligible relatives: one’s father, his brother, his father’s brother, his mother’s brother, his sister’s husband, his father’s sister’s husband (i.e., uncle by marriage), his mother’s sister’s husband (uncle by marriage), his mother’s husband (i.e., stepfather), his father-in-law and his brother-in-law; these people plus their sons, their sons-in-law and the litigant’s own stepson (but not the stepson’s son or son-in-law). Rabbi Yosi said that our mishna reflects the position of Rabbi Akiva but originally they taught the litigant’s uncle, his uncle’s son, everyone in his line of inheritance. (Getting back to Rabbi Akiva’s position,) everyone related to the litigant at the time is ineligible. If someone was formerly a relative but is no longer (i.e., an ex-son-in-law), he is eligible. Rabbi Yehuda says that even if the litigant’s daughter died, if she and her husband have children, then the litigant and the son-in-law are still considered related.

Sanhedrin 3:5

A litigant’s friend and his enemy are also ineligible. A friend is one who participated in his wedding and an enemy is one who did not speak with him for three days out of hatred. The Sages said that Jews are not suspected of such behavior (i.e., that they would lie in court out of friendship or animosity).