From one of the central Christian theologians of the Early Church, Athanasius (c.296-298 - 373), we are reading his work On the Incarnation (De Incarnatione Verbi Dei).
No matter what your skill level is in reading ancient primary texts, you should be reading about the best from the best. When we desire to learn what early Christianity believed about the person of Jesus Christ, one of the best is Athanasius, who through this work developed significantly the Christian view of God as Trinity.
”For God is good—or rather, of all goodness he is fountainhead, and it is impossible for one who is good to be mean or grudging about anything. Grudging existence to none therefore, he made all things out of nothing through his own Word, our Lord Jesus Christ; and of all these his earthly creatures he reserved especial mercy for the race of men.” (I.i)