Just finished a serious and challenging book called Christianity and the Doctrine of Non-Dualism, by an anonymous French "Monk of the West" (although his identity is known). This is an area that is particularly dear to me, since I find myself equally drawn to Yoga and Christianity. Being that I am unable to choose between the two, perhaps it is my destiny to try to recooncile them. Of course, that doesn't mean blending them, which would only reconsully both. Rather, it's more like "cross referencing." In so doing, one must proceed very cautiously, because it is possible to use words in a manner they were never intended just to achieve a superficial ecumenism.
For example, the idea that Jesus was "just another guru" -- or an instance of the avatar principle (the descent of the divine in human form, or "Godman") -- would be a non-starter, doing violence to both Christianity and Yoga. One has to be willing to consider the idea that avatars exist, but that there is only one begotten son. Likewise, although "ascended masters" have surely passed this way, to restrict Jesus to the category of a mere fleshlight would be to miss the whole point.
In the end, the Monk makes only the claim that Orthodox Christianity and the classic Vedanta of Shankara are not incompatible, as opposed to being identical. For example, Meister Eckhart, according to no less an authority than Vladimir Lossky, expresses "a vision of the unity of being which is not pantheistic monism, but rather a Christian 'non-dualism,' appropriate to the idea of the world created ex nihilo by the all-powerful God of the Bible -- 'He who is.'" In other words, at the very least, Christianity is capacious enough to formulate a doctrine of non-dualism in its own terms...
In the preface to the book, Alvin Moore describes Christianity at its core as "a bhaktic esoterism," while in common practice it is "an exoteric religion of love," thereby accessible to "a considerable sector or mankind." He goes on to say that since only God can truly know God, to know God is to "become him." Or, if that doesn't sound quite right, our knowledge of God "is God's knowledge of Himself through man as instrument," a formulation that might well have come from the pen of Meister Eckhart.
Now, exactly what is Vedanta? Unlike Christianity, there is no doctrinal unity in Hinduism, but Vedanta is essentially the experiential confirmation of "the mystery of the divine Absolute, the transcendent Self which constitutes the deepest stratum of our being." It is the highest sacred and esoteric wisdom of Hinduism, preserved in the Upanishads, which one might roughly say are to eternity as the Bible is to time. That is, the Bible is primarily a linear account of the historical dealings of God and man, whereas the Upanishads are mainly timeless accounts of purely vertical encounters between the ancient "Vedic seers" and the Absolute.
In turn, the Bhagavad Gita may be thought of as an attempt to "horizontalize" the vertical message of the Upanishads in a mythological form for a more popular audience. This is only superficially analogous to the Bible, because the Bible's theology is derived from the story, so to speak, whereas in the case of the Gita, the story is the instantiation of the theology (although there are purely philosophical/theological parts of the Bible, e.g., Proverbs, and purely metaphysical rants by Krishna, the god-man of the Gita).
I suppose it's no coincidence that my favorite Christian theologians (e.g., Dionysius, Eckhart, Nicholas of Cusa, John Scottus Eriugena) often sound like vedic seers. For example, I might well have cited Nicholas to support the Cosmogenesis section of my book: