Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary

Ehud had escaped whilst the servants of Eglon were waiting, and had passed the stone quarries and reached Seirah. Seirah is a place that is never mentioned again; and, judging from the etymology (the hairy), it was a wooded region, respecting the situation of which all that can be decided is, that it is not to be sought for in the neighbourhood of Jericho, but "upon the mountains of Ephraim" (Jdg 3:27). For when Ehud had come to Seirah, he blew the trumpet "upon the mountains of Ephraim," to announce to the people the victory that was placed within their reach by the death of Eglon, and to summon them to war with the Moabites, and then went down from the mountain into the plain near Jericho; "and he was before them," i.e., went in front as their leader, saying to the people, "Follow me; for Jehovah has given your enemies the Moabites into your hand." Then they went down and took (i.e., took possession of) the fords near Jericho (see at Jos 2:7), למואב, either "from the Moabites" or "towards Moab," and let no one (of the Moabites) cross over, i.e., escape to their own land.