`Abdu’l-Bahá was born on May 23, and the early believers, particularly in the West, wanted to celebrate the day of His birth. Since May 23 was also the day that the Báb declared his mission, ‘Abdu’l-Bahá said that this date should be exclusively associated with the Báb, and under no circumstances be celebrated as his day of birth. However, as the Bahá’ís begged for a day to be celebrated as `Abdu’l-Bahá’s birthday, he gave them November 26, exactly 181 days after the ascension of Bahá’u’lláh, to be observed as the day of the appointment of the Centre of the Covenant. This Holy Day was originally known as the Greatest Festival in Persia, because `Abdu’l-Bahá was known as the Greatest Branch; in the West, it became known as the Day of the Covenant.
I bear witness to Thy unity and Thy oneness, and that Thou art God, and that there is none other God beside Thee. Thou hast, verily, revealed Thy Cause, fulfilled Thy Covenant, and opened wide the door of Thy grace to all that dwell in heaven and on earth. Blessing and peace, salutation and glory, rest upon Thy loved ones, whom the changes and chances of the world have not deterred from turning unto Thee, and who have given their all, in the hope of obtaining that which is with Thee. Thou art, in truth, the Ever-Forgiving, the All-Bountiful. ((Baha’u’llah, from the Medium Obligatory Prayer, Prayers and Meditations by Baha’u’llah, p. 316))
A Covenant in the religious sense is a binding agreement between God and man, whereby God requires of man certain behaviour in return for which He guarantees certain blessings, or whereby He gives man certain bounties in return for which He takes from those who accept them an undertaking to behave in a certain way. There is, for example, the Greater Covenant which every Manifestation of God makes with His followers, promising that in the fulness of time a new Manifestation will be sent, and taking from them the undertaking to accept Him when this occurs. There is also the Lesser Covenant that a Manifestation of God makes with His followers that they will accept His appointed successor after Him. If they do so, the Faith can remain united and pure. If not, the Faith becomes divided and its force spent. It is a Covenant of this kind that Bahá’u’lláh made with His followers regarding ‘Abdu’l-Bahá and that ‘Abdu’l-Bahá perpetuated through the Administrative Order. ((Universal House of Justice, The Compilation of Compilations vol. I, p. 111))
In the past, every divine Revelation has faced the forces of opposition from without, and division from within, and these have sundered these faith communities. Bahá’u’lláh promises that these forces will not divide His Faith, but will only cause its light of concord and integrity to burn more brightly. He established a written Covenant, appointing His eldest son `Abdu’l-Bahá as His Successor, and directing all of the Bahá’ís to turn to Him. He also provided for the institutions of the Guardianship and the Universal House of Justice to protect its unity, and this was confirmed in` Abdu’l-Bahá’s Covenant–His Will and Testament. The explicit assurance of these twin Covenants is that the Bahá’í Faith will never break into sects, that it is divinely protected from schism. This Covenant is unique in the spiritual history of humanity and is one of the most wonderful features of the Bahá’í Faith. (( http://bahai-covenant.blogspot.ca/2010/12/covenant-protects-from-schism.html))
Here’s a wonderful story to illustrate the covenant:
It was the custom of Shoghi Effendi to walk on Mount Carmel, and at times he invited the Persian men believers to walk with him. They would walk a few paces behind him, out of respect. Ali-Kuli Khan was a member of one of these groups of men, and at one point Shoghi Effendi stopped, and turned to the men, and said, “Although I am Abdu’l-Baha’s successor, I am not His equal. His station is far greater than my own.” Then he turned, and continued walking. Ali-Kuli Khan burst into tears. When he finished weeping, one of his fellow pilgrims asked him, “What Shoghi Effendi said was very beautiful, but why did it have such an effect on you?” Ali-Kuli Khan answered, “Many years ago, I was here on Pilgrimage during the days of Abdu’l-Baha. One day I was walking with Him on the slopes of Mount Carmel, and He stopped, at that very same spot, and turned to me and said, “Although I am the Successor to Baha’u’llah, I am not His equal. His station is far, far greater than My own.” And of course, as we were walking behind the beloved Guardian, I recalled the sweetness of that moment. And then I saw that we were approaching that spot where the Master had spoken, and to my astonishment, Shoghi Effendi stopped, and spoke at that same spot. And when he said what he did, then I understood the greatness of this Cause.” ((http://bahai-storytelling.blogspot.ca/2010/11/day-of-covenant.html))
Today no power can conserve the oneness of the Baha’i world save the Covenant of God; otherwise differences like unto a most great tempest will encompass the Baha’i world. It is evident that the axis of the oneness of the world of humanity is the power of the Covenant and nothing else. Had the Covenant not come to pass, had it not been revealed from the Supreme Pen and had not the Book of the Covenant, like unto the ray of the Sun of Reality, illuminated the world, the forces of the Cause of God would have been utterly scattered and certain souls who were the prisoners of their own passions and lusts would have taken into their hands an axe, cutting the root of this Blessed Tree. Every person would have pushed forward his own desire and every individual aired his own opinion! ((Abdu’l-Baha, Tablets of the Divine Plan, p. 51))
Marzieh Gail writes about the circumstances at the time of the passing of the Prophet Muhammad, and that He did not make a written Covenant appointing His Successor. He had already verbally appointed His son-in-law, Ali:
“As Muhammad lay dying, He called for writing materials to appoint His successor again; but ‘Umar said, ‘Pain is deluding God’s Messenger; we have God’s book, which is enough.’ And they wrangled at His bedside, whether to bring the materials or no. And the Prophet sent them from Him. He was praying in a whisper, when He ascended.” ((“Dawn Over Mount Hira,” p. 8))
The same thing almost happened in the Baha’i Faith, but it was prevented by the written Covenant of Baha’u’llah, appointing His Successor, Abdu’l-Baha. Toward the end of His life, one day when He was alone in His room with Abdu’l-Baha in the Mansion of Bahji, Baha’u’llah directed Abdu’l-Baha to gather up all of His Tablets, which were in various places around the room, and to place them all in His two leather briefcases. This command was given in such a tone, that Abdu’l-Baha instantly understood that this signified that Baha’u’llah would soon be leaving this world, and He burst into tears. As Abdu’l-Baha was gathering the Tablets and placing them in the two briefcases, He was weeping.
However, there was one Tablet Baha’u’llah did not direct Abdu’l-Baha to put into the briefcases–His Last Will and Testament. This document, which does not bear a date, nor Baha’u’llah’s signature or seal, was written by Baha’u’llah entirely in His own hand. In it, He directs all of the believers to turn to Abdu’l-Baha. Baha’u’llah directed Abdu’l-Baha to keep this document personally, and separate from His other Tablets. A few weeks later, Baha’u’llah ascended to the immortal realm.
On the following day, Abdu’l-Baha was washing the sacred body of Baha’u’llah and wrapping it in shrouds, to prepare the body for burial. Mirza Muhammad-Ali, Abdu’l-Baha’s younger brother, was desirous of leadership. He had even claimed, during Baha’u’llah’s lifetime, to be a Manifestation of God. Seeing his opportunity, he said, while Abdu’l-Baha was washing the sacred body of Baha’u’llah, that the water might spill on the two briefcases, and he suggested that he move them. Abdu’l-Baha was deeply involved in the sacred act of washing His Father’s body, and He hardly noticed, and motioned His assent.
Mirza Muhammad-Ali stole those Tablets, most of which are still not in the hands of the Faith. He looked through all of them for some Writing with which he could undermine Abdu’l-Baha’s authority, and claim leadership for himself. Baha’u’llah’s foresight prevented this from happening, and assured that Abdu’l-Baha would be the Head of the Faith. ((http://bahai-storytelling.blogspot.ca/2010/11/day-of-covenant.html))
Our limbs, our members, O my Lord, bear witness to Thy unity and oneness. Send down upon us Thy strength and power, that we may become steadfast in Thy Faith and may aid Thee among Thy servants. Illumine our eyes, O my Lord, with the effulgence of Thy beauty, and enlighten our hearts with the splendors of Thy knowledge and wisdom. Write us up, then, with those who have fulfilled their pledge to Thy Covenant in Thy days, and who, through their love for Thee, have detached themselves from the world and all that is therein. Powerful art Thou to do what Thou pleasest. No God is there beside Thee, the All-Powerful, the Omniscient, the Supreme Ruler, the Help in Peril, the Self-Subsisting. (Baha’u’llah, Prayers and Meditations by Baha’u’llah, p. 173)
O my Lord and my Hope! Help Thou Thy loved ones to be steadfast in Thy mighty Covenant, to remain faithful to Thy manifest Cause, and to carry out the commandments Thou didst set down for them in Thy Book of Splendors; that they may become banners of guidance and lamps of the Company above, wellsprings of Thine infinite wisdom, and stars that lead aright, as they shine down from the supernal sky. Verily, Thou art the Invincible, the Almighty, the All-Powerful. (Abdu’l-Baha, Baha’i Prayers, 2002 U.S. Edition, pp. 71-72)