St. Justin Martyr (c. 100 – 165) taught that all truth came from the Logos, or Word, of God. Therefore, whatever truth was stated by any human being at any time, anywhere, was the result of the influence of the immanent Logos within him/her; and was, therefore, Christian. It was later generations of Christians that claimed for the institutional Christian church a total monopoly on truth as its sole source and repository… as it does to this day.
“the teachings of Plato are different from those of Christ, … they are not in all respects similar, as neither are those of the others, Stoics, and poets, and historians. For each man spoke well in proportion to the share he had of the spermatic word [spermatikos logos; the Logos inherent in all humans], seeing what was related to it. But they who contradict themselves on the more important points appear not to have possessed the heavenly wisdom, and the knowledge which cannot be spoken against. Whatever things were rightly said among all men, are the property of us Christians… For all the writers were able to see realities darkly through the sowing of the implanted word [spermatikos logos] that was in them. For the seed and imitation imparted according to capacity is one thing, and quite another is the thing itself, of which there is the participation and imitation according to the grace which is from Him.” Second Apology, 13.