The fatherhood of God has had a central, if increasingly controversial, place in Christian thinking about God. Yet although Christians referred to God as Father from the earliest days of the faith, it was not until Athanasius in the fourth century that the idea of God as Father became a topic of sustained analysis. Looking at the genesis of Athanasius' understanding of divine fatherhood against the background of Alexandrian tradition, Widdicombe demonstrates how the concept came to occupy such a prominent place in Christian theology.
A fine monograph by Peter Widdicombe. Widdicombe explores the way that Origen developed the notion of God as the Father of the Son, and then briefly examines how Arius and others tried to handle the same theme before turning to Athanasius. On the whole, it looks like Athanasius wasn't just more faithful to the scriptures (which he was) and to the traditions of the church (which he also was), but even to Origen as the mighty influence behind the Alexandrian theological tradition.
Athanasius, of course, ably argued what has come to be a commonplace in Christian theology: that, without the deity of the Son precisely as Son of the Father, the grand depths of salvation in the Christian understanding would be impossible, and so on Arius' scheme we could not be united with God. Arius should've listened to what he must've read in Origen's writings: "Let him who assigns a beginning to the Word of God or the Wisdom of God beware, lest he utter impiety against the unbegotten Father himself, in denying that he was always a Father" (De Principiis 1.2.2-3).
Widdicombe's 1994 book is slow-going and a bit obscure, but it's an excellent contribution to scholarship.