The Kitáb-i-Aqdas
181.any reference to “Vicegerency” debar you from the sovereignty of Him Who is the Vicegerent of God   ¶167
The word here translated “Vicegerency” is, in the original Arabic, “viláyat,” which has a range of meanings including “vicegerency,” “guardianship,” “protectorship” and “successorship.” It is used in relation to God Himself, to His Manifestation, or to those who are the appointed Successors of a Manifestation.
In this verse of the Aqdas, Bahá’u’lláh warns against allowing such concepts to blind one to the “sovereignty” of the new Divine Manifestation, the true “Vicegerent of God.”