Only here in New Testament. The simple verb χειροτονέω, to appoint, occurs Act 14:23; 2Co 8:19; and originally means to stretch out the hand for the purpose of giving a vote. Hence to elect by show of hands, and generally to appoint. Plato uses the word of the election of leaders of choruses (“Laws,” 765). In later ecclesiastical usage it signified ordain, as bishops or deacons.
Who (οἵτινες)
The compound pronoun marks them more strongly as belonging to the class of eye-witnesses.