Unto the Lord in Mizpeh - This city was situated on the confines of Judah and Benjamin, and is sometimes attributed to the one, sometimes to the other. It seems that there was a place here in which the Lord was consulted, as well as at Shiloh; in 1 Maccabees 3:46, we read, In Maspha was the place where they prayed aforetime in Israel. These two passages cast light on each other. Some think that Shiloh is meant, because the ark was there; but the phrase before the Lord may signify no more than meeting in the name of God to consult him, and make prayer and supplication. Wherever God's people are, there is God himself; and it ever was true, that wherever two or three were assembled in his name, he was in the midst of them.
The “congregation” is the technical term for the whole community of the Israelite people. Its occurrence here is an indication of the early date of these transactions.
Unto the Lord in Mizpeh - The phrase “unto the Lord”, implies the presence of the tabernacle (Judges 11:11 note). Mizpeh in Benjamin Joshua 18:26, from its connection with Bethel and Ramah, is probably meant here. It is the same as that which appears as a place of national assembly in 1 Samuel 7:5; 1 Samuel 10:17; 2 Kings 25:23-25. It must have been near Shiloh and Gibeah, and in the north of Benjamin. The Benjamites were duly summoned with the other tribes; so that their absence was contumacious Judges 20:3.