That is, they went out on forays together. They were in a sense soldiers of fortune making their living by hiring out as mercenaries, scouts, or guards. Like David at a later time (1 Sam. 22:1, 2; 1 Sam 25:1-35), they received gifts for protecting wealthy people from robbers, or for driving back small incursions of desert invaders. From this type of activity Jephthah gained a wide reputation for bravery, sagacity, and initiative. The epistle to the Hebrews (11:32) mentions him as a man of faith.
Tob.
A place by the name of Ish-tob (“Tob,” RSV) was included with the list of the small Aramaean states to the east of Jordan from among whom the Ammonites hired mercenary troops in their wars with David (2 Sam. 10:6-8).
Vain men.
Literally, “empty men,” that is, poor persons without property, employment, or training wherewith to earn a living, except their ability to fight. It does not necessarily mean that they were men without moral qualities, but rather that they were unsuccessful, discontented, needy men.