“shofar.” The ram’s horn trumpet, not the metal trumpet.
“in the hill country of Ephraim.” Ehud was from the tribe of Benjamin (Judg. 3:15), but in this record, he went to rally an army from Ephraim. Ephraim was a stronger and more prominent tribe than Benjamin, and that may have been why. Also, we do not know for certain when the war between Benjamin and Israel occurred in which most of the men of Benjamin were killed (Judg. 19-21). If it was before this, then the Benjamites would not have been able to muster an army.
“and he was before them.” Ehud still needed to take the lead and give the people confidence in what they were doing. Good leaders know when to lead and when to encourage others to lead. Ehud was a great leader and he went before his men to encourage and inspire them, and to set an example for them to see.