Here follows a quote from the work of Rudolf Steiner about the meaning of Augustine for the church. I am finishing my reflections about Augustine with this quote.
Augustine's method of thinking told him that since the Christ event other conditions had begun for souls seeking the spirit in place of those which had existed previously. For him it was firmly established that in Christ Jesus there had been revealed in the outer historical world what the mystic had sought through preparation in the Mysteries.
One of his most significant utterances is the following: "What is now called the Christian religion already existed among the ancients, and was not lacking at the very beginnings of the human race. When Christ appeared in the flesh, the true religion already in existence received the name of Christian." Two paths of development were possible for such a mode of thinking. One is that if the human soul develops within it the forces leading it to the cognition of its true self, if it but goes far enough, it will also come to cognition of the Christ and of everything connected with him. This would have been a Mystery knowledge enriched through the Christ event. The other way is that actually taken by Augustine, by which he became the great example for his successors. It consists in cutting off the development of the forces of the soul at a certain point and in receiving the ideas connected with the Christ event from written accounts and oral traditions. Augustine rejected the first way as springing from pride of soul; he thought the second way was the way of true humility. Thus he says to those who wished to follow the first way: "You may find peace in the truth, but for this, humility is needed, which does not suit your proud neck." On the other hand he was filled with boundless inward happiness by the fact that since the "appearance of Christ in the flesh" it was possible to say that experience of the spiritual can be attained by every soul which goes as far as it can in seeking within itself, and then, in order to reach the highest, has faith in what the written and oral traditions of the community of Christians tell about the Christ and his revelation. On this point he says: "What bliss, what abiding enjoyment of supreme and true good is offered to us, what serenity, what a breath of eternity! How shall I describe it? It has been expressed, as far as it could be, by those great incomparable souls who we admit have beheld and still behold ... We reach a point at which we acknowledge how true is what we have been commanded to believe and how well and beneficiently we have been brought up by our mother the Church, and of what benefit was the milk given by the Apostle Paul to the little ones ..."(It is beyond the scope of this book to give an account of the alternative method of thinking which is evolved from the Mystery knowledge enriched through the Christ event. The description of this method will be found in my outline of the 'Geheimwissenschaft'.) — Whereas in pre-Christian times one who wished to seek the spiritual foundations of existence was necessarily directed to the way of the Mysteries, Augustine was able to say, even to those souls who could find no such path within themselves: Go as far as you can on the path of cognition with your human powers; from there, faith (belief) will carry you up into the higher spiritual regions. — It was only going one step further to say: It is in the nature of the human soul to be able to arrive only at a certain stage of cognition through its own powers; from there it can advance further only through faith, through belief in the written and oral tradition. This step was taken by the spiritual movement which assigned to natural perception a certain sphere above which the soul could not rise by its own efforts, but everything which lay beyond this sphere was made an object of belief which has to be supported by written and oral tradition, and by faith in its representatives.
(from: Christianity As Mystical Fact, GA 8, Augustine and the church).
The Cathedral in Chartres
Augustine and the exoteric christianity by Mieke Mosmuller