The elders are in a panic. The whole congregation had offered peace to Benjamin, to restore them to the community. The elders involved themselves to bring about this peace process. Their reputations are on the line. Their anxiety is seen in their use of a forceful verb, they commanded the people of Benjamin.
This differs from the earlier message from Israel to Benjamin: Peace
(Judges 21:13).1
20 And they commanded the people of Benjamin, saying, “Go and lie in ambush in the vineyards