and subject of dispute among theologians. The fact is that one
cannot think in realistic fashion of the "deus homo factus" without
thinking oneself out of it. It is exceedingly instructive to find that,
in some passages, even a man like Irenaeus was obliged to advance from
the creed of the one God-man to the assumption of two independent
existences in Christ, an assumption which in the earlier period has only
"Gnostic" testimony in its favour. Before Irenaeus' day, in fact, none
but these earliest theologians taught that Jesus Christ had two natures,
and ascribed to them particular actions and experiences. The Gnostic
distinction of the Jesus _patibilis_ ("capable of suffering") and the
Christ [Greek: apathes] ("impassible") is essentially identical with the
view set forth by Tertullian adv. Prax., and this proves that the
doctrine of the two natures is simply nothing else than the Gnostic,
i.e., scientific, adaptation of the formula: "filius dei filius hominis
factus." No doubt the old early-Christian interest still makes itself
felt in the _assertion_ of the one person. Accordingly we can have no
historical understanding of Tertullian's Christology or even of that of
Irenaeus without taking into account, as has not yet been done, the
Gnostic distinction of Jesus and Christ, as well as those old
traditional formulae: "deus passus, deus crucifixus est" ("God suffered,
God was crucified").[607]

But beyond doubt the prevailing conception of Christ in Irenaeus is the
idea that there was the most complete unity between his divine and human
natures; for it is the necessary consequence of his doctrine of
redemption, that "_Jesus Christus factus est, quod sumus nos, uti nos
perficeret esse quod et ipse_"[608] ("Jesus Christ became what we are in
order that we might become what he himself is"). But, in accordance with
the recapitulation theory, Irenaeus developed the "factus est quod sumus
nos" in such a way that the individual portions of the life of Christ,
as corresponding to what we ought to have done but did not do, receive
the value of saving acts culminating in the death on the cross. Thus he
not only regards Jesus Christ as "salvation and saviour and saving"
("salus et salvator et salutare"),[609] but he also views his whole life
as a work of salvation. All that has taken place between the conception
and the ascension is an inner necessity in this work of salvation. This
is a highly significant advance beyond the concep