• Matthew 18:15-17
  "Moreover if your brother sins against you, go and tell him his fault between you and him alone. If he hears you, you have gained your brother. But if he will not hear, take with you one or two more, that "by the mouth of two or three witnesses every word may be established." And if he refuses to hear them, tell it to the church. But if he refuses even to hear the church, let him be to you like a heathen and a tax collector.
   
• Deuteronomy 19:15
  “One witness shall not rise against a man concerning any iniquity or any sin that he commits; by the mouth of two or three witnesses the matter shall be established.
   

Related Scriptures

• Matthew 7:1-2
  "Judge not, that you be not judged. For with what judgment you judge, you will be judged; and with the measure you use, it will be measured back to you.