Today, the most important affair is firmness in The Covenant, because firmness in The Covenant wards off differences.
In former cycles no distinct Covenant was made in writing by the Supreme Pen; no distinct personage was appointed to be the Standard differentiating falsehood from truth, so that whatsoever he said was to stand as truth and that which he repudiated was to be known as falsehood. At most, His Holiness Jesus Christ gave only an intimation, a symbol, and that was but an indication of the solidity of Peter’s faith. When he mentioned his faith, His Holiness said, Thou art Peter”—which means rock—’and upon this rock will I build my church.’ This was a sanction of Peter’s faith; it was not indicative of his (Peter) being the expounder of the Book, but was a confirmation of Peter’s faith.
But in this Dispensation of the Blessed Beauty (BAHA’U’LLAH) among its distinctions is that He did not leave people in perplexity. He entered into a Covenant and Testament with the people. He appointed a CENTER OF THE COVENANT. He wrote with His own pen and revealed it in the Kitab-I-Akdas, the Book of Laws, and Kitab-I-Ah’d, the Book of the Covenant, appointing him (Abdul-Baha) the Expounder of the Book. You must ask him (Abdul-Baha) regarding the meanings of the texts of the verses. Whatsoever he says is correct. Outside of this, in numerous Tablets He (BAHA’U’LLAH) has explicitly recorded it, with clear, sufficient, valid and forceful statements. In the Tablet of THE BRANCH He explicitly states: Whatsoever THE BRANCH says is right, or correct; and every person must obey THE BRANCH with his life, with his heart, with his tongue. Without his will, not a word shall anyone utter. This is an explicit text of the Blessed Beauty. So there is no excuse left for anybody. No soul shall, of himself, speak anything: Whatsoever his (Abdul-Baha’s) tongue utters, whatsoever his pen records, that is correct; according to the explicit text of BAHA’U’LLAH in the Tablet of THE BRANCH.
Abdu’l-Baha, Star of The West, Vol. 3, No. 14, Pg. 9
So firm and mighty is this Covenant that from the beginning of time until the present day no religious Dispensation hath produced its like. It is indubitably clear that the pivot of the oneness of mankind is nothing else but the power of the Covenant. Know thou that the ‘Sure Handle’ mentioned from the foundation of the world in the Books, the Tablets and the Scriptures of old is naught else but the Covenant and the Testament. The lamp of the Covenant is the light of the world, and the words traced by the Pen of the Most High a limitless ocean. The Lord, the All-Glorified, hath, beneath the shade of the Tree of Anísá (Tree of Life), made a new Covenant and established a great Testament. Hath such a Covenant been established in any previous Dispensation, age, period or century? Hath such a Testament, set down by the Pen of the Most High, ever been witnessed? No, by God! The power of the Covenant is as the heat of the sun which quickeneth and promoteth the development of all created things on earth. The light of the Covenant, in like manner, is the educator of the minds, the spirits, the hearts and souls of men.
All praise and thanksgiving be unto the Blessed Beauty, for calling into action the armies of His Abhá Kingdom, and sending forth to us His never-interrupted aid, dependable as the rising stars. In every region of the earth hath He supported this single, lonely servant, at every moment hath He made known to me the signs and tokens of His love. He hath cast into a stupor all those who are clinging to their vain illusions, and made them infamous in the sight of high and low. He hath caused those who run after their fads and fancies to become objects of general reproach, and hath exposed the arrogant to public view; He hath made those of the friends who proved infirm of faith to serve as a warning to every beholder, and hath caused the leaders of those who waver to love but themselves and sink down in self-conceit. Meanwhile, by the power of His might, He hath made this broken-winged bird to rise up before all who dwell on earth. He hath shattered the serried ranks of the rebellious, and hath given the victory to the hosts of salvation, and breathed into the hearts of those who stand firm in the Covenant and Testament the breath of everlasting life.
Abdu’l-Baha, excerpted from Selections #195