I think most of the principles of most religions overlap - so that if you believe in one, you inadvertently believe in the others too.
That is a very nice observation and I also fully agree...here, let me show you more:
Tao Teh Ching: "The Tao that can be spoken is not the eternal Tao
The name that can be named is not the eternal name..."
The Bible: "Jesus told them, "Truly, I tell all of you emphatically, before there was an Abraham, I AM!" John 8:58
The Upanishads: "Brahman is not grasped by the eye, nor by speech, nor by the other senses, nor by penance or good works. A man becomes pure through serenity of intellect; thereupon, in meditation, he beholds Him who is without parts." - Mundaka Upanishad 3.1.8
Dhammapada: "Those who mistake the unessential to be essential and the essential to be unessential, dwelling in wrong thoughts, never arrive at the essential". - Stanza 11
Bhagavad Gita: "But this unmanifest is not the original divinity of the Being; there is another state of existence, an unmanifest superconsciousness beyond this cosmic manifestation, which is eternally self-seated , changeless and infinite. It does not perish with the perishing of all existence". BG 8:20
The Qu'ran: "No vision can grasp Him, but His grasp is over all vision; He is above all comprehension, yet is acquainted with all things". Q6.103
The Bible: "For my thoughts are not your thoughts, neither are your ways my ways, says the Lord. For as the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts." - Isaiah 55.8-9
Lotus Sutra: "At this time the World-honored One serenely arose from meditation and addressed Shariputra, "The wisdom of all the Buddhas is infinitely profound and immeasurable. The portal to this wisdom is difficult to understand and difficult to enter. Neither men of learning nor men of realization are able to comprehend it." Sutra 2.
The Upanishads: “‘In the beginning there was Existence, One only, without a second. Some say that in the beginning there was nonexistence only, and that out of that the universe was born. But how could such a thing be? How could existence be born of non-existence? No, my son, in the beginning there was Existence alone–One only, without a second. He is the truth. He is the Self. And that, Svetaketu, THAT ART THOU." Chhandogya Upanishad 6:2:3
Yeah, I got this pretty bad, haven't I? lol