To the house of God - It should be, "to Bethel." See Judges 20:18.

The people came to the house of God - Literally, the people came בית־אל to Bethel; this is considered as the name of a place by the Chaldee, Syriac, Arabic, and Septuagint.
And wept sore - Their revenge was satisfied, and now reflection brings them to contrition for what they had done.

And the people came to the house of God,.... Not to the city Bethel, as the Targum, Septuagint, and other versions, but to Shiloh, where were the tabernacle and ark; and this is to be understood of the army after they had utterly destroyed the Benjaminites: hence we read of the camp in Shiloh, Judges 21:12, here they came not so much to rejoice, and be glad, and to return thanks for the victory they had at last obtained, as to lament the unhappy case of the tribe of Benjamin, and to have counsel and advice, and consider of ways and means to repair their loss:
and abode there till even before God; fasting and praying, instead of feasting and rejoicing:
and lifted up their voices, and wept sore; not so much, or at least not only for the 40,000 Israelites that were slain, but for the tribe of Benjamin, in danger of being lost, as follows.

THE PEOPLE BEWAIL THE DESOLATION OF ISRAEL. (Judges 21:1-15)
the people came to the house of God, . . . and lifted up their voices, and wept sore--The characteristic fickleness of the Israelites was not long in being displayed; for scarcely had they cooled from the fierceness of their sanguinary vengeance, than they began to relent and rushed to the opposite extreme of self-accusation and grief at the desolation which their impetuous zeal had produced. Their victory saddened and humbled them. Their feelings on the occasion were expressed by a public and solemn service of expiation at the house of God. And yet this extraordinary observance, though it enabled them to find vent for their painful emotions, did not afford them full relief, for they were fettered by the obligation of a religious vow, heightened by the addition of a solemn anathema on every violator of the oath. There is no previous record of this oath; but the purport of it was, that they would treat the perpetrators of this Gibeah atrocity in the same way as the Canaanites, who were doomed to destruction; and the entering into this solemn league was of a piece with the rest of their inconsiderate conduct in this whole affair.