C. F. Keil and Franz Delitzsch on Judges 19:1

War of the Congregation with the Tribe of Benjamin on Account of the Crime at Gibeah - Judges 19-20

This account belongs to the times immediately following the death of Joshua, as we may see form the fact that Phinehas, the son of Eleazar, the contemporary of Joshua, was high priest at that time (Jdg 20:28). In Judg 19 we have an account of the infamous crime committed by the inhabitants of Gibeah, which occasioned the war; in Judg 20 the war itself; and in Judg 21 an account of what was afterwards done by the congregation to preserve the tribe of Benjamin, which was almost annihilated by the war.

Jdg  19:1-2

Infamous Crime of the Inhabitants of Gibeah. - Jdg 19:1-14. At the time when there was no king in Israel, a Levite, who sojourned (i.e., lived outside a Levitical town) in the more remote parts of the mountains of Ephraim, took to himself a concubine out of Bethlehem in Judah, who proved unfaithful to him, and then returned to her father’s house. הר־אפרים ירכּתי, the hinder or outermost parts of the mountains of Ephraim, are the northern extremity of these mountains; according to Jdg 19:18, probably the neighbourhood of Shiloh. עליו תּזנה, “she played the harlot out beyond him,” i.e., was unfaithful to her husband, and then went away from him,” back to her father’s house.