We are not careful to demand that a judge for a court of three possess all these qualities. He must, however, possess seven attributes: wisdom, humility, the fear of God, a loathing for money, a love for truth; he must be a person who is beloved by people at large, and must have a good reputation.
All of these qualities are mentioned explicitly in the Torah. When relating Moses' statements concerning the appointment of judges, Deuteronomy 1:13 mentions: "Men of wisdom and understanding." This refers to wisdom.
The verse continues: "Beloved by your tribes." This refers to those who are appreciated by people at large. What will make them beloved by people? Conducting themselves with a favorable eye and a humble spirit, being good company, and speaking and conducting their business with people gently.
When relating Jethro's advice to Moses to appoint judges, Exodus 18:21 speaks of "men of power." This refers to people who are mighty in their observance of the mitzvot, who are very demanding of themselves, and who overcome their evil inclination until they possess no unfavorable qualities, no trace of an unpleasant reputation, even during their early manhood, they were spoken of highly. The phrase "men of power" also implies that they should have a courageous heart to save an oppressed person from the one oppressing him, as Exodus 2:17 states: "And Moses arose and delivered them."
Just as we see that Moses was humble; so, too, every judge should be humble. Exodus 18:21 continues: "God-fearing" - the intent is obvious. It mentions: "men who hate profit," i.e., people who do not become overly concerned even about their own money. They do not pursue the accumulation of money, for anyone who is overly concerned about wealth will ultimately be overcome by want.
The verse continues: "men of truth," i.e., people who pursue justice because of their own inclination; they love truth, hate crime, and flee from all forms of crookedness.