Judges 21:5

21:5 The Israelites asked, “Who from all the Israelite tribes has not assembled before the Lord?” They had made a solemn oath that whoever did not assemble before the Lord at Mizpah must certainly be executed. ¹ 

¹ tn Heb “A great oath there was concerning the one who did not go up before the Lord at Mizpah, saying, ‘He must surely be put to death.’”