What Was The Office of Evangelist?

In the gospel church-state there were evangelists also, as they are mentioned, Eph. 4:11; Acts 21:8; 2 Tim. 4:5; -- gospellers, preachers of the gospel, distinct from the ordinary teachers of the churches Things, I confess, are but obscurely delivered concerning this sort of men in Scripture, their office being not designed unto a continuance. Probably the institution of it was traduced from the temporary ministry of the seventy before mentioned.