Bahá’í Sacred Writings, Bahá’u’lláh, #9

Regard thou the one true God as One Who is apart from, and immeasurably exalted above, all created things. The whole universe reflecteth His glory, while He is Himself independent of, and transcendeth His creatures. This is the true meaning of Divine unity. He Who is the Eternal Truth is the one Power Who exerciseth undisputed sovereignty over the world of being, Whose image is reflected in the mirror of the entire creation. All existence is dependent upon Him, and from Him is derived the source of the sustenance of all things. This is what is meant by Divine unity; this is its fundamental principle….

The essence of belief in Divine unity consisteth in regarding Him Who is the Manifestation of God and Him Who is the invisible, the inaccessible, the unknowable Essence as one and the same. By this is meant that whatever pertaineth to the former, all His acts and doings, whatever He ordaineth or forbiddeth, should be considered, in all their aspects, and under all circumstances, and without any reservation, as identical with the Will of God Himself. This is the loftiest station to which a true believer in the unity of God can ever hope to attain. Blessed is the man that reacheth this station, and is of them that are steadfast in their belief.