To be honest....you have to go back to Hinduism...Zoroastrianism and others. I guess this illustrates what has been said about many streams, one river:
"one river of truth, but many streams falling into it." "This, said Clement of Alexandria (150?-2150?), is perennially the vision of the Christian scholar, man's mind, with its multiple ways of reaching truth, fulfilled by a river of truth proceeding directly from God." (
http://archives.nd.edu/ward/ward13.htm)
Interesting...again, from Wiki -
http://en.wikipedia.org/wiki/Clement_of_Alexandria
"He united Greek philosophical traditions with Christian doctrine and valued gnosis that with communion for all people could be held by common Christians."
Of course, the later church considered some of his teachings erroneous and he was removed from the list of saints....ahhh politics.
http://www.hypotyposeis.org/weblog/2007/...dhism.html
He also said: "Among the Indians are some who follow the precepts of Buddha, whom for his extraordinary sanctity they have honored as a god." (tr. John Ferguson).
On this passage, John Ferguson, Clement of Alexandria: Stromateis Books 1-3 (Fathers of the Church 85; Washington, D.C.: CUA, 1991), 76, n.338, notes:
The reference to Buddha is exceptionally interesting: Pantaenus [Clement’s predecessor in Alexandra] may have travelled in the East. But the veneration of the Buddha does not give him the title of a god, although he is the Lord.
According to Eusebius, Hist. eccl. 5.10.2-3, when Pantaenus traveled to the East, he found an old copy of Matthew:
... One of these was Pantaenus, and it is said that he went to the Indians, and the tradition is that he found there that among some of those there who had known Christ the Gospel according to Matthew had preceded his coming; for Bartholomew, one of the apostles, had preached to them and had left them the writing of Matthew in Hebrew letters, which was preserved until the time mentioned. (tr. Kirsopp Lake)
The identity of this find remains obscure."
And...another who has used the metaphor...just a Google find:
"...Richard Foster is one person who has popularised it. It is the image of streams. Spirituality is like a river in which many streams - or traditions - mix and mingle and flow together."
(
http://www.carey.ac.nz/pauls_blog/2007/0...banks.html)