Chapter VII The Persons that became at that Time Leaders of Knowledge falsely so-called
1 As the churches throughout the world were now shining like the most brilliant stars, and faith in our Saviour and Lord Jesus Christ was flourishing among the whole human race, the demon who hates everything that is good, and is always hostile to the truth, and most bitterly opposed to the salvation of man, turned all his arts against the Church.4 In the beginning he armed himself against it with external persecutions.
2 But now, being shut off from the use of such means, he devised all sorts of plans, and employed other methods in his conflict with the Church, using base and deceitful men as instruments for the ruin of souls and as ministers of destruction. Instigated by him, impostors and deceivers, assuming the name of our religion, brought to the depths of ruin such of the believers as they could win over, and at the same time, by means of the deeds which they practiced, turned away from the path which leads to the word of salvation those who were ignorant of the faith.
What Eusebius points out are two great shaping influences on Christianity: persecution and heresy, and specifically, the heresy of Gnosticism. There is no understanding the course the early church took unless you know something about those two things: persecution and Gnosticism. That isn’t all there is to know, of course, but those circumstances are crucial.
In thinking about it, I have at last discovered what my long irritation with persons who are keen on finding modern instances of Gnosticism is. It is that when they do this, they suggest the main value of learning about Gnosticism is to be able to identify it in the church today. Now, one can’t say that there is no legitimacy to that practice. There is value to showing how some things are Pelagian, some Arian, and so on. But I think it is limited (very limited), and not to be made much of.
The real value of understanding Gnosticism is not so that we can identify them now, but so that we can understand ourselves. Christianity was shaped under those circumstances. God sent the gnostics, if you will, he permitted them to arise in that unique context of a world in which there was still prevailing paganism (what rubbish to say there are pagans today, none of the accused actually believe in any gods at all) with its attitude shaped by the kind of community pagan life provided. This attitude made the Christians react, and the result was the beginning of theology. Christians began to think about how to study Scripture carefully (hermeneutics) and about organizing the true interpretation (doctrinal formulation and theology, eventually, systematized as it becomes elaborate). We were destined to be a doctrinal people, but Gnosticism was the circumstance God used to generate an attitude of concern for that thing without which there is no real Christian community: orthodoxy.