C. F. Keil and Franz Delitzsch on Judges 20:18

Jdg 20:18

Before opening the campaign the Israelites went to Bethel, to inquire of God which tribe should commence the war, i.e., should fight at the head of the other tribes (on the fact itself, see Jdg 1:1); and God appointed the tribe of Judah, as in Jdg 1:2. They went to Bethel,Rendered “the house of God” in the English version. - Tr. not to Shiloh, where the tabernacle was standing, because that place was too far from the seat of war. The ark of the covenant was therefore brought to Bethel, and Phinehas the high priest inquired of the Lord before it through the Urim and Thummim (Jdg 20:27, Jdg 20:28). Bethel was on the northern boundary of the tribe of Benjamin, and was consecrated to this purpose before any other place by the revelations of God which had been made to the patriarch Jacob there (Gen 28 and 35).