13 Then the whole assembly sent an offer of peace to the Benjamites at the rock of Rimmon.

Read Judges 21:13 Using Other Translations

And the whole congregation sent some to speak to the children of Benjamin that were in the rock Rimmon, and to call peaceably unto them.
Then the whole congregation sent word to the people of Benjamin who were at the rock of Rimmon and proclaimed peace to them.
The Israelite assembly sent a peace delegation to the remaining people of Benjamin who were living at the rock of Rimmon.