Paul Tillich, A History Of Christian Thought
Irenaeus, Tertullian, and Hippolytus.
Last time we finished with the description of that great movement called Gnosticism and which, more exactly, should be regarded as the wave of religious syncretism running from the East to the West, existing in many groups and forms and entering also Christianity. I gave you some of their main ideas. In opposition to – and partly also in acceptance of – the Gnostic ideas, the first great Christian theologians developed their systems: Irenaeus, Tertullian and Hippolytus. The defense against attacks from outside was made in terms of the Logos doctrine. But now some of the spirit of the world which was conquered by Christianity, entered Christianity itself. The fight now had to be waged against a Christianized paganism. But such a fight is never simply a negation: it is always reception, also.
The result of this partial rejection, and partial reception, of the generally religious mood of that time is what we call “early Catholicism.” The people with whom we now have to deal are important because they represent early Catholicism, expressing these ideas which grew out of the acceptance and rejection of the pagan religious movement of that time.
In order to do so, they accepted the Logos doctrine created by the Apologists, but they now brought it constructively – and not only apologetically – into a framework of Bible and tradition. In doing so they partly deprived it of its dangerous implications, one of them of course being the possibility of relapse into polytheism – tri-theism or duo-theism. It is the greatness of these people, Irenaeus and Tertullian, that they saw these dangers, used the Logos doctrine, and developed constructively the theological ideas in relationship to the religious movements of their time.