For it must be said in general that the apostolic fathers are not men of brilliance or penetrating theological insight; rather, their central contribution lies not in their elaboration of the faith but in their call for obedience to the ecclesiastical hierarchy, their warnings against heresy, and their simple commendation of the faith, even in the face of martyrdom. There is no doubt that a man like Polycarp, for example, was a great Christian leader and a great man of faith, but a great theologian he was not. 
(Gary Badcock, Light of Truth and Fire of Love: A Theology of the Holy Spirit, 36)