Athanasius is our first hero...
296/8 Athanasius born
303-5 Diocletian’s great persecution
312 Conversion of Constantine
318 Arius begins to teach that there was a time when the Son was not
325 Council of Nicea “begotten, not made, of the same being of the Father”
328 Alexander dies, Athanasius becomes bishop of Alexandria`
335-7 1st exile of Athanasius, writes Against the Heathen and On the Incarnation
336 Death of Arius (born 256)
339-46 2nd exile
356-62 3rd exile, writes Against the Arians, Life of Anthony (and sparks a legacy of monasticism)
373 Dies following two further exiles.
Athanasius finds himself caught up in a great fight - against the world - and against Arius. The key idea of this comes in Against the Arians, 1.34: "Therefore it is more pious and more accurate to signify God from the Son and call Him Father, than to name Him from His works only and call Him Unoriginate"
Where Arius' best idea of God is the uncaused cause, the originate - discerned from creation Athanasius says we can do better than that. We can do better than a deity who has attributes and resources and achievements. From that Arius can seemingly get no better than an impersonal god. Athanasius follows Jesus (Luke 10) and says that we know the Father as the father of the Son, and the Son as the son of the Father.
"Therefore it is more pious and more accurate to signify God from the Son and call Him Father, than to name Him from His works only and call Him Unoriginate"
God then is basically relational - as is humanity in God's image. This lack is easy to see in Islam or with the Jehovah's Witnesses buts slips into the church when we are fearful to be Trinitarian, imagining that Trinity is some obscure doctrine rather than who God has revealed himself to be. Singing songs about God's great power without calling on him as the Father of the Son in whom we too become sons may betray the same. Our God is Triune, relational, personal and that is good.
More in The Breeze of the Centuries by Mike Reeves or read Against the Arians