From the Writings and Utterances of ‘Abdu’l-Bahá
...It is incumbent upon everyone not to take any step without consulting the Spiritual Assembly, and they must assuredly obey with heart and soul its bidding and be submissive unto it, that things may be properly ordered and well arranged. Otherwise every person will act independently and after his own judgement, will follow his own desire, and do harm to the Cause.
(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” (Wilmette: Bahá’í Publishing Trust, 1974), p.21) 
The prime requisites for them that take counsel together are purity of motive, radiance of spirit, detachment from all else save God, attraction to His Divine Fragrances, humility and lowliness amongst His loved ones, patience and long-suffering in difficulties and servitude to His exalted Threshold. Should they be graciously aided to acquire these attributes, victory from the unseen Kingdom of Bahá shall be vouchsafed to them.... The members thereof must take counsel together in such wise that no occasion for ill-feeling or discord may arise. This can be attained when every member expresseth with absolute freedom his own opinion and setteth forth his argument. Should any one oppose, he must on no account feel hurt for not until matters are fully discussed can the right way be revealed. The shining spark of truth cometh forth only after the clash of differing opinions. If after discussion a decision be carried unanimously, well and good; but if, the Lord forbid, differences of opinion should arise, a majority of voices must prevail.
(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”, pp. 21-22) 
... The first condition is absolute love and harmony amongst the members of the assembly. They must be wholly freed from estrangement and must manifest in themselves the Unity of God, for they are the waves of one sea, the drops of one river, the stars of one heaven, the rays of one sun, the trees of one orchard, the flowers of one garden. Should harmony of thought and absolute unity be non-existent, that gathering shall be dispersed and that assembly be brought to naught. The second condition: they must when coming together turn their faces to the Kingdom on High and ask aid from the Realm of Glory. They must then proceed with the utmost devotion, courtesy, dignity, care and moderation to express their views. They must in every matter search out the truth and not insist upon their own opinion, for stubbornness and persistence in one’s views will lead ultimately to discord and wrangling and the truth will remain hidden. The honoured members must with all freedom express their own thoughts, and it is in no wise permissible for one to belittle the thought of another, nay, he must with moderation set forth the truth, and should differences of opinion arise a majority of voices must prevail, and all must obey and submit to the majority. It is again not permitted that any one of the honoured members object to or censure, whether in or out of the meeting, any decision arrived at previously though that decision be not right, for such criticism would prevent any decision from being enforced. In short, whatsoever thing is arranged in harmony and with love and purity of motive, its result is light, and should the least trace of estrangement prevail the result shall be darkness upon darkness.... If this be so regarded, that assembly shall be of God, but otherwise it shall lead to coolness and alienation that proceed from the Evil One.... Should they endeavour to fulfil these conditions the Grace of the Holy Spirit shall be vouchsafed unto them, and that assembly shall become the centre of the Divine blessings, the hosts of Divine confirmation shall come to their aid, and they shall day by day receive a new effusion of Spirit.
(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”, pp. 22-23) 
One consecrated soul is preferable to a thousand other souls. If a small number of people gather lovingly together, with absolute purity and sanctity, with their hearts free of the world, experiencing the emotions of the Kingdom and the powerful magnetic forces of the Divine, and being at one in their happy fellowship, that gathering will exert its influence over all the earth. The nature of that band of people, the words they speak, the deeds they do, will unleash the bestowals of Heaven, and provide a foretaste of eternal bliss. The hosts of the Company on high will defend them, and the angels of the Abhá Paradise, in continuous succession, will come down to their aid.
(“Selections from the Writings of ‘Abdu’l-Bahá”, (Haifa: Bahá’í World Centre, 1982), sec. 39, p. 81) 
If they agree upon a subject, even though it be wrong, it is better than to disagree and be in the right, for this difference will produce the demolition of the divine foundation. Though one of the parties may be in the right and they disagree that will be the cause of a thousand wrongs, but if they agree and both parties are in the wrong, as it is in unity the truth will be revealed and the wrong made right.
(“Bahá’í World Faith: Selected Writings of Bahá’u’lláh and ‘Abdu’l-Bahá” (Wilmette: Bahá’í Publishing Trust, 1976), p. 411) 
The question of consultation is of the utmost importance, and is one of the most potent instruments conducive to the tranquillity and felicity of the people. For example, when a believer is uncertain about his affairs, or when he seeketh to pursue a project or trade, the friends should gather together and devise a solution for him. He, in his turn, should act accordingly. Likewise in larger issues, when a problem ariseth, or a difficulty occurreth, the wise should gather, consult, and devise a solution. They should then rely upon the one true God, and surrender to His Providence, in whatever way it may be revealed, for divine confirmations will undoubtedly assist. Consultation, therefore, is one of the explicit ordinances of the Lord of mankind.
Man must consult on all matters, whether major or minor, so that he may become cognizant of what is good. Consultation giveth him insight into things and enableth him to delve into questions which are unknown. The light of truth shineth from the faces of those who engage in consultation. Such consultation causeth the living waters to flow in the meadows of man’s reality, the rays of ancient glory to shine upon him, and the tree of his being to be adorned with wondrous fruit. The members who are consulting, however, should behave in the utmost love, harmony and sincerity towards each other. The principle of consultation is one of the most fundamental elements of the divine edifice. Even in their ordinary affairs the individual members of society should consult.
Every one of the friends should highly praise the other and each should regard himself as evanescent and as naught in the presence of others. All matters should be consulted upon in the meeting and whatever is the majority vote should be carried out. I swear by the one true God, it is better that all should agree on a wrong decision, than for one right vote to be singled out, inasmuch as single votes can be sources of dissension, which lead to ruin. Whereas, if in one case they take a wrong decision, in a hundred other cases they will adopt right decisions, and concord and unity are preserved. This will offset any deficiency, and will eventually lead to the righting of the wrong.
The purpose of consultation is to show that the views of several individuals are assuredly preferable to one man, even as the power of a number of men is of course greater than the power of one man. Thus consultation is acceptable in the presence of the Almighty, and hath been enjoined upon the believers, so that they may confer upon ordinary and personal matters, as well as on affairs which are general in nature and universal.
For instance, when a man hath a project to accomplish, should he consult with some of his brethren, that which is agreeable will of course be investigated and unveiled to his eyes, and the truth will be disclosed. Likewise on a higher level, should the people of a village consult one another about their affairs, the right solution will certainly be revealed. In like manner, the members of each profession, such as in industry, should consult, and those in commerce should similarly consult on business affairs. In short, consultation is desirable and acceptable in all things and on all issues.
(Cited in a letter dated 15 February 1922 written by Shoghi Effendi to the National Spiritual Assembly of Persia) 
Regarding thy question about consultation of a father with his son, or a son with his father, in matters of trade and commerce, consultation is one of the fundamental elements of the foundation of the Law of God. Such consultation is assuredly acceptable, whether between father and son, or with others. There is nothing better than this. Man must consult in all things for this will lead him to the depths of each problem and enable him to find the right solution.
The honoured members of the Spiritual Assembly should exert their efforts so that no differences may occur, and if such differences do occur, they should not reach the point of causing conflict, hatred and antagonism, which lead to threats. When you notice that a stage has been reached when enmity and threats are about to occur, you should immediately postpone discussion of the subject, until wranglings, disputations, and loud talk vanish, and a propitious time is at hand.
Settle all things, both great and small, by consultation. Without prior consultation, take no important step in your own personal affairs. Concern yourselves with one another. Help along one another’s projects and plans. Grieve over one another. Let none in the whole country go in need. Befriend one another until ye become as a single body, one and all...3
Every meeting which is organized for the purpose of unity and concord will be conducive to changing strangers into friends, enemies into associates, and ‘Abdu’l-Bahá will be present in His heart and soul with that meeting.
(“Tablets of Abdul-Baha Abbas”, vol. 2 (Chicago: Bahá’í Publishing Society, 1915), p. 553) 
In this Cause consultation is of vital importance, but spiritual conference and not the mere voicing of personal views is intended. In France I was present at a session of the senate, but the experience was not impressive. Parliamentary procedure should have for its object the attainment of the light of truth upon questions presented and not furnish a battleground for opposition and self-opinion. Antagonism and contradiction are unfortunate and always destructive to truth. In the parliamentary meeting mentioned, altercation and useless quibbling were frequent; the result, mostly confusion and turmoil; even in one instance a physical encounter took place between two members. It was not consultation but comedy.
The purpose is to emphasize the statement that consultation must have for its object the investigation of truth. He who expresses an opinion should not voice it as correct and right but set it forth as a contribution to the consensus of opinion, for the light of reality becomes apparent when two opinions coincide. A spark is produced when flint and steel come together. Man should weigh his opinions with the utmost serenity, calmness and composure. Before expressing his own views he should carefully consider the views already advanced by others. If he finds that a previously expressed opinion is more true and worthy, he should accept it immediately and not willfully hold to an opinion of his own. By this excellent method he endeavors to arrive at unity and truth. Opposition and division are deplorable. It is better then to have the opinion of a wise, sagacious man; otherwise, contradiction and altercation, in which varied and divergent views are presented, will make it necessary for a judicial body to render decision upon the question. Even a majority opinion or consensus may be incorrect. A thousand people may hold to one view and be mistaken, whereas one sagacious person may be right. Therefore, true consultation is spiritual conference in the attitude and atmosphere of love. Members must love each other in the spirit of fellowship in order that good results may be forthcoming. Love and fellowship are the foundation.
The most memorable instance of spiritual consultation was the meeting of the disciples of Jesus Christ upon the mount after His ascension. They said, “Jesus Christ has been crucified, and we have no longer association and intercourse with Him in His physical body; therefore, we must be loyal and faithful to Him, we must be grateful and appreciate Him, for He has raised us from the dead, He made us wise, He has given us eternal life. What shall we do to be faithful to Him?” And so they held council. One of them said, “We must detach ourselves from the chains and fetters of the world; otherwise, we cannot be faithful.” The others replied, “That is so.” Another said, “Either we must be married and faithful to our wives and children or serve our Lord free from these ties. We cannot be occupied with the care and provision for families and at the same time herald the Kingdom in the wilderness. Therefore, let those who are unmarried remain so, and those who have married provide means of sustenance and comfort for their families and then go forth to spread the message of glad-tidings.” There were no dissenting voices; all agreed, saying, “That is right.” A third disciple said, “To perform worthy deeds in the Kingdom we must be further self-sacrificing. From now on we should forego ease and bodily comfort, accept every difficulty, forget self and teach the Cause of God.” This found acceptance and approval by all the others. Finally a fourth disciple said, “There is still another aspect to our faith and unity. For Jesus’ sake we shall be beaten, imprisoned and exiled. They may kill us. Let us receive this lesson now. Let us realize and resolve that though we are beaten, banished, cursed, spat upon and led forth to be killed, we shall accept all this joyfully, loving those who hate and wound us.” All the disciples replied, “Surely we will—it is agreed; this is right.” Then they descended from the summit of the mountain, and each went forth in a different direction upon his divine mission.
This was true consultation. This was spiritual consultation and not the mere voicing of personal views in parliamentary opposition and debate.
(“The Promulgation of Universal Peace: Talks Delivered by ‘Abdu’l-Bahá during His Visit to the United States and Canada in 1912”, 2nd ed. (Wilmette: Bahá’í Publishing Trust, 1982), pp. 72–73) 
The first duty of the members is to effect their own unity and harmony, in order to obtain good results. If there be no unity, or the Committee becomes the cause of inharmony, undoubtedly, it is better that it does not exist....
Therefore, when the unity of the members of the Committee is established, their second duty is to read the verses and communes, to be in a state of commemoration and mindfulness, that they may see each other as if in the presence of God.
(Published in “Star of the West”, vol. 8, no. 9 (20 August 1917), p. 114)