“Irenaeus’ work marks the birth of Christian theology. With it, theology emerges as a reflection on the world of revealed facts, a reflection which is not just a tentative, partial approximation but achieves the miracle of a complete and organised image in the mind of faith. The first and second post-apostolic generations had indeed made a vigorous start on this task, producing works of inimitable brilliance, but these remained occasional works like Clement’s glowing letter to the Corinthians; steep, high, narrow confessions like the blazing letters of Ignatius; attempts at synthesis which remained trapped in the contemplation of a detail or the putting together of elements only just learnt and mastered, like the Didache and so much in the Apologists. But no sooner does Theophilus of Antioch see, however indistinctly, that his task is to present salvation history within the framework of world history, than he runs aground on the sandbank of a dry-as-dust chronology, while the believer’s spiritual indignation at the world of lies of the pagan pantheon is expressed in him, in Hermias and in Tatian, in jibes which leave one looking for a more sovereign refutation and treatment. Typical of the form of this theology in search of itself is its most valuable example, the Letter to Diognetus, in which one finds sections without internal structure or coherence side by side with precious intuitions and formulations of an intensity possibly never reached again (especially §§ 5–6). The most important preparatory work is done by Justin, whose calm, magnificent intelligence gathers and arranges the scattered pieces and assembles them around a centre which is not just conceived, but really seen, the Logos everywhere present in the world who in the Judaeo-Christian history of salvation nevertheless entered the world and finally became flesh. Without Justin, to whose material he constantly goes back, Irenaeus would never have reached his heights, but his relation to him is that of the genius to the man of ability, like that of Mozart to Christian Bach and his many contemporaries: they gave him the forms out of which they could make only a clever game. Justin, for all his cleverness, has a certain dullness; his industry cannot overcome a feeling of boredom. Irenaeus radiates from every pore; his utterance derives not from academic and pious knowledge, but from a creative sight of the glowing central core. The height of the spring betrays the force of the pressure which drives it up, and here the stimulus is not the general enemy, paganism, but a personal one, fully recognised and fully mastered for the first time by Irenaeus, who not only sees through him to the heart but is also enabled by him to employ his intellectual and existential indignation at such a radical falsifying of the truth in an attempt to capture and represent the centre of reality. Justin and the Apologists had no such enemy. The ordinary pagan religion was too amorphous, and their petitions to the emperor required them to spare it and discover what was good and usable in it; and in the same way the dialogue with the Jews had to be conducted in such a way that it constantly shifted between intimate agreement and an assault on their blindness. But Gnosis, which, largely with the tools and materials of the Bible, had erected a totally un-Christian structure of the highest intellectual and religious quality and won over many Christians, Gnosis was the opponent Christian thought needed in order fully to find itself. Every Christian theology is conditioned by its situation, or it would not be the theology of a historical revelation. Every book of the Bible, every statement of Jesus, is conditioned by its situation, because fully historical. Great Christian theology shares in the mystery of Scripture, in as much as it too possesses, in and through its conditioning by its situation, that special vitality which secures and preserves its supra-temporal validity. Though talking to an opponent long-since vanished, Irenaeus is as fresh and relevant today as ever; his work shares the power of perpetual renewal which he says the Holy Spirit gives to the Christian faith and the Church which contains it. The power may come from the faith, but the opponent was the occasion for the crystallisation. So, at the beginning of the history of theology, we have an illustration of the same historical law which governs the history of thought from Plato onwards: it is only the turning away from the ‘aesthetic’ and its conquest which provides the power and opens eyes to see real beauty.”
– from Hans Urs von Balthasar,The Glory of the Lord: A Theological Aesthetics. Volume II; Studies in Theological Style—Clerical Styles (Ignatius Press, 1984)