This study portrays Cyril of Alexandria as exegete and theologian through an examination of his Commentary on the Gospel of John. It begins with an attempt to place Cyril and his commentary within their context. Cyril's multifaceted personality becomes evident in the years before he became bishop. A Christian Egyptian and a citizen of the Roman Empire, raised in the cosmopolitan city of Alexandria and trained as an ascetic in Scetis, a student of Scripture and rhetoric, Cyril became a writer, an exegete, and a reader in the Church of Alexandria. This work argues that Cyril wrote his Commentary on the Gospel of John early in his writing career, almost a decade before becoming bishop.

Cyril's commentary on the Johannine Gospel reveals his exegetical method and his strong Trinitarian theology. Influenced by his rhetorical training, he begins with the literal meaning and then directs his readers to the deeper, spiritual, hidden, and enigmatic meaning of the text. Cyril's spiritual interpretation aims to disclose the type of Christ and discover the deep and hidden meaning of scripture. The Trinity is the framework within which Cyril articulates his understanding of the Incarnation and redemption. The unity, oneness, and indivisibility of Christ are preserved at all times and under all conditions, not only within his own nature but also within the Trinity. The commentary also focuses the nature and work of the Holy Spirit: the indwelling of the Spirit is the beginning of the newness of life.