From the Writings of Bahá’u’lláh
The Great Being saith: The heaven of divine wisdom is illumined with the two luminaries of consultation and compassion. Take ye counsel together in all matters, inasmuch as consultation is the lamp of guidance which leadeth the way, and is the bestower of understanding.
(“Tablets of Bahá’u’lláh Revealed after the Kitáb-i-Aqdas” [rev. ed.], (Haifa: Bahá’í World Centre, 1982), p. 168) 
Say: No man can attain his true station except through his justice. No power can exist except through unity. No welfare and no well-being can be attained except through consultation.
Consultation bestoweth greater awareness and transmuteth conjecture into certitude. It is a shining light which, in a dark world, leadeth the way and guideth. For everything there is and will continue to be a station of perfection and maturity. The maturity of the gift of understanding is made manifest through consultation.
Such matters should be determined through consultation, and whatever emergeth from the consultation of those chosen, that indeed is the command of God, the Help in Peril, the Self-Subsisting.
In all things it is necessary to consult. This matter should be forcibly stressed by thee, so that consultation may be observed by all. The intent of what hath been revealed from the Pen of the Most High is that consultation may be fully carried out among the friends, inasmuch as it is and will always be a cause of awareness and of awakening and a source of good and well-being.
It behooveth them to be the trusted ones of the Merciful among men and to regard themselves as the guardians appointed of God for all that dwell on earth. It is incumbent upon them to take counsel together and to have regard for the interests of the servants of God, for His sake, even as they regard their own interests, and to choose that which is meet and seemly. Thus hath the Lord your God commanded you. Beware lest ye put away that which is clearly revealed in His Tablet. Fear God, O ye that perceive.
(Cited in a letter dated 5 March 1922 written by Shoghi Effendi to the Bahá’ís of the United States and Canada, published in “Bahá’í Administration: Selected Messages 1922–1932” [rev. ed.] (Wilmette: Bahá’í Publishing Trust, 1977), p. 21) 
If in the first group of people who have gathered, unanimity is not achieved, new people shall be added, after which a group equal in number to the Greatest Name1 or fewer or greater shall be chosen from their midst by lots; whereupon the consultation shall be renewed; whatever is the result shall be obeyed. If the second time opinions again differ, repeat the process a third time. This time obey the majority vote. Verily He directeth whom He willeth to the straight Path.2
(From a Tablet - translated from the Arabic and Persian)