Mat 18:16 But if he will not hear [you, then] take with you one or two more, that in the mouth of two or three witnesses every word may be established.

This verse continues Christ's teaching that matters should be resolved as privately between individuals as possible. His goal is to eliminate the role of society and social authority in mediating disputes between individuals. He saw those impersonal relationships as the source of social problems rather than their cure.

This ideas was first brought up in the Lord's Prayer, when he teaches us to pray to be delivered from not temptations, but trials, which means generally the idea of being tested but specifically held the idea of social judgments. He touches on this idea several more times.

If you cannot resolve a dispute completely privately, between the two people involved, the next step is to bring in one or two other people to act as witnesses. These witnesses are not part of a trial. They are there to put the words that are spoken in their place, that is, to put them in perspective. The witnesses outside perspective makes it easier for both parties in a dispute to see the situation objectively and thereby resolve it.

Alternative versions: But if he will not listen, call in with you one or two more, that in the mouth of two or three witnesses every word may be put in its place.

"Take" is from paralambanô, which means "to take to oneself," "to associate with," "to call in," and "to invite." With the word for witness, martus, it specifically means "to call in witnesses."

"Mouth" is stoma, which means "mouth" and "the foremost part" of something. For example, the blade of a weapon is a stoma.

"Witnesses" is from martus, which means "witness" or "witnesses" and later came to mean "martyr."

"Word" is from rhêma, which means "that which is spoken," "word," "saying," "word for word," "subject of speech," and "matter."

"Establish" is from tithêmi (histemi), which menas "to set," "to put," and "to place." Like the English words "put" and "set," it has a number of specific meanings from "to put down [in writing]," "to bury," "to establish," "to make," "to cause," and "to assign."