Sanhedrin, Chapter Three, Mishnah Five
Mishnah five continues to discuss those people who are disqualified from testifying or acting as judges.
1) A friend or an enemy [is disqualified].
a) A friend: this is ones groomsman.
b) An enemy: anyone whom he has not spoken to in three days because of anger.
2) They replied: Israelites are not suspected of such.
The first clause in the mishnah states that one may not testify or judge in a trial involving ones friend or enemy. The next two clauses define the first clause. A friend who is disqualified from testifying or judging is a mans groomsman, a person who helped him celebrate his wedding. An enemy is anyone with whom one has not spoken for three days due to anger.
It must be assumed that the first three clauses are a continuation of Rabbi Judahs words, begun in the previous mishnah. The Sages in section 1d respond to Rabbi Judah by claiming that Jews are not suspected of lying in court because they are testifying with regards to a friend or enemy. Therefore, a person may testify and judge in cases involving a friend or an enemy.