Jamieson, Fausset and Brown on Judges 21:21-22

21-22. daughters of Shiloh come out to dance in dances--The dance was anciently a part of the religious observance. It was done on festive occasions, as it is still in the East, not in town, but in the open air, in some adjoining field, the women being by themselves. The young women being alone indulging their light and buoyant spirits, and apprehensive of no danger, facilitated the execution of the scheme of seizing them, which closely resembles the Sabine rape in Roman history. The elders undertook to reconcile the families to the forced abduction of their daughters. And thus the expression of their public sanction to this deed of violence afforded a new evidence of the evils and difficulties into which the unhappy precipitancy of the Israelites in this crisis had involved them.