Man is My mystery, and I am his mystery.

Shrine of Bahá'u'lláh
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How resplendent the luminaries of knowledge that shine in an atom, and how vast the oceans of wisdom that surge within a drop! To a supreme degree is this true of man, who, among all created things, hath been invested with the robe of such gifts, and hath been singled out for the glory of such distinction.
For in him are potentially revealed all the attributes and names of God to a degree that no other created being hath excelled or surpassed. All these names and attributes are applicable to him. Even as He hath said: “Man is My mystery, and I am his mystery.”
 Manifold are the verses that have been repeatedly revealed in all the Heavenly Books and the Holy Scriptures, expressive of this most subtle and lofty theme. Even as He hath revealed: “We will surely show them Our signs in the world and within themselves.” Again He saith: “And also in your own selves: will ye not, then, behold the signs of God?” And yet again He revealeth: “And be ye not like those who forget God, and whom He hath therefore caused to forget their own selves.” In this connection, He Who is the eternal King—may the souls of all that dwell within the mystic Tabernacle be a sacrifice unto Him—hath spoken: “He hath known God who hath known himself.”

Gleanings From the Writings of Bahá’u’lláh P.178