Further to my last post on why the Vincentian Canon is not a reliable or workable rule for establishing what is "catholic doctrine" (one of the few subjects on which I find myself in agreement with John Henry Newman), I submit this quote from the doctoral dissertation of the Scottish theologian Thomas F. Torrance on the decline of the doctrines of grace in the early church soon after the Apostolic period ended.
The theme of striving for justification (hence, justification by works) either through martyrdom or by strict adherence to "The Way", a version of the Christian life strongly influenced by Judaism, marks the writings of the Fathers of the immediate post-Apostilic period, and inevitably led to the loss of the Cross of Christ as the ground of our justification and the power for Christian life, as was so powerfully exhibited by Paul in his letter to the Romans (see the Didache or Barnabas for examples of this tendency).
When reading these authors, look out also for the sense in which they (e.g. Clement) use the term "faith" - more often than not it refers to acceptance of the doctrines of Christ misinterpreted in terms of submission to an ethical path that leads to heaven.
These themes of striving for salvation and ethical submission to Christ later pass into monasticism and to this day mark the ascetical literature of Eastern Orthodoxy.
Anyway, here's Torrance...
Salvation is wrought, they thought, certainly by divine pardon but on the ground of repentance [self-amendment before God], not apparently on the ground of the death of Christ alone. There is no doubt about the fact that the early Church felt it was willing to go all the way to martyrdom, but it felt that it was in that way the Christian made saving appropriation of the Cross, rather than by faith…It was not seen that the whole of salvation is centred in the person and the death of Christ…Failure to apprehend the meaning of the Cross and to make it a saving article of faith is surely the clearest indication that a genuine doctrine of grace is absent.
Thomas F Torrance
The Doctrine of Grace in the Apostolic Fathers (1959).