1 Timothy 5:19-21

Do not accept an accusation against an elder unless it is based on [the testimony of at least] two or three witnesses. [Deut 19:15] As for those [elders] who continue in sin, reprimand them in the presence of all [the congregation], so that the rest will be warned. I solemnly charge you in the presence of God and of Christ Jesus and of His chosen angels that you guard and keep these rules without bias, doing nothing out of favoritism.