Judges 20:12

Then shalt thou inquire, and make search, and ask diligently; and, behold, if it be truth, and the thing certain, that such abomination is wrought among you;

When thou comest nigh unto a city to fight against it, then proclaim peace unto it.

And the children of Israel sent unto the children of Reuben, and to the children of Gad, and to the half tribe of Manasseh, into the land of Gilead, Phinehas the son of Eleazar the priest, And with him ten princes, of each chief house a prince throughout all the tribes of Israel; and each one was an head of the house of their fathers among the thousands of Israel. And they came unto the children of Reuben, and to the children of Gad, and to the half tribe of Manasseh, unto the land of Gilead, and they spake with them, saying, Thus saith the whole congregation of the LORD, What trespass is this that ye have committed against the God of Israel, to turn away this day from following the LORD, in that ye have builded you an altar, that ye might rebel this day against the LORD?

Moreover if thy brother shall trespass against thee, go and tell him his fault between thee and him alone: if he shall hear thee, thou hast gained thy brother. But if he will not hear thee, then take with thee one or two more, that in the mouth of two or three witnesses every word may be established. And if he shall neglect to hear them, tell it unto the church: but if he neglect to hear the church, let him be unto thee as an heathen man and a publican. Verily I say unto you, Whatsoever ye shall bind on earth shall be bound in heaven: and whatsoever ye shall loose on earth shall be loosed in heaven.

If it be possible, as much as lieth in you, live peaceably with all men.