And it came to pass, when he was come, that he blew a trumpet in the mountain of Ephraim, and the children of Israel went down with him from the mount, and he before them. (Judges 3:27)
In view of the fact that Ehud was of the tribe of Benjamin, it may seem strange that he did not go to the nearer settlements of his own tribe. Either strong Moabite garrisons were stationed there, or he felt the Benjamites were too cowed to respond to his call to battle. The tribe of Ephraim, the most numerous and most aggressive of the tribes, responded quickly to his battle call.