But the Covenant of God and His Testament is a bounty to the righteous and a curse to the wicked.

‘Abdu’l-Bahá, Tablets of ‘Abdu’l-Bahá v2, p. 438

O thou whom my heart addresses! Know thou, verily, the Covenant is an Orb which shines and gleams forth unto the universe. Verily, its light will dispel darkness, its sea will cast out the thick foam of suspicions upon the shore of perdition.

‘Abdu’l-Bahá, Bahá’í Scriptures, p. 320

The Covenant of God ... is a lifeboat and ark of salvation.  All true followers of the Blessed Perfection are sheltered and protected in this ark.  Whoever leaves it, trusting in his own will and strength, will drown and be destroyed.

‘Abdu’l-Bahá, Daily Readings from the Bahá’í Teachings, p. 128

He feels you . . .  should devote particular attention to deepening the friends in the Covenant, which is the ark of safety for every believer.

Shoghi Effendi, Japan Will Turn Ablaze, p. 54

The Ark of Bahá’u’lláh's Covenant has, ever since those days, been steadily pursuing its course contemptuous of the storms of bitter misfortune that have raged, and which must continue to assail it, as it forges ahead towards the promised haven of undisturbed security and peace.

Shoghi Effendi, The World Order of Bahá’u’lláh, p. 84

The believers need to be deepened in their knowledge and appreciation of the Covenants of both Bahá’u’lláh and ‘Abdu’l-Bahá. This is the stronghold of the Faith of every Bahá’í, and that which enables him to withstand every test and the attacks of the enemies outside the Faith, and the far more dangerous, insidious, lukewarm people inside the Faith who have no real attachment to the Covenant, and consequently uphold the intellectual aspect of the teachings while at the same time undermining the spiritual foundation upon which the whole Cause of God rests. He feels you and your dear family should do all you can to teach the believers the Will and Testament to strengthen their understanding of its important provisions; for all the authority of the administrative bodies, as well as of the Guardian himself, is mainly derived from this tremendous document.

Shoghi Effendi, The Light of Divine Guidance v II, p. 82

The Covenant is the "axis of the oneness of the world of humanity" because it preserves the unity and integrity of the Faith itself and protects it from being disrupted by individuals who are convinced that only their understanding of the Teachings is the right one -- a fate that has overcome all past Revelations. The Covenant is, moreover, embedded in the Writings of Bahá’u’lláh Himself. Thus, as you clearly see, to accept Bahá’u’lláh is to accept His Covenant; to reject His Covenant is to reject Him.

The Universal House of Justice, Messages 1963 to 1986, p. 518

The House of Justice hopes that these explanations will help you to understand some of the aspects of the Faith that have been troubling you. The crux of the matter, as you realize, is the acceptance of spiritual authority and what this implies. You express the fear that the authority conferred upon ‘Abdu’l-Bahá, the Guardian and the Universal House of Justice could lead to a progressive reduction in the "available scope for personal interpretation," and that "the actual writings of the Manifestation will have less and less import," and you instance what has happened in previous Dispensations. The House of Justice suggests that, in thinking about this, you contemplate the way the Covenant of Bahá’u’lláh has actually worked, and you will be able to see how very different its processes are from those of, say, the development of the law in Rabbinical Judaism or the functioning of the Papacy in Christianity. The practice in the past in these two religions, and also to a great extent in Islam, has been to assume that the Revelation given by the Founder was the final, perfect revelation of God's Will to mankind, and all subsequent elucidation and legislation has been interpretative in the sense that it aimed at applying this basic Revelation to the new problems and situations that have arisen. The Bahá’í premises are quite different. Although the Revelation of Bahá’u’lláh is accepted as the Word of God and His Law as the Law of God, it is understood from the outset that Revelation is progressive, and that the Law, although the Will of God for this Age, will undoubtedly be changed by the next Manifestation of God. Secondly, only the written text of the Revelation is regarded as authoritative. There is no Oral Law as in Judaism, no Tradition of the Church as in Christianity, no Hadith as in Islam. Thirdly, a clear distinction is drawn between interpretation and legislation. Authoritative interpretation is the exclusive prerogative of ‘Abdu’l-Bahá and the Guardian, while infallible legislation is the function of the Universal House of Justice.

The Universal House of Justice, Messages 1963 to 1986, p. 517-518

The relationship of God with man in this Covenant is somewhat similar to the relationship between the principal of a school and the child. As soon as a child goes to school for the first time, he enters into a covenant with the school principal, although often without really knowing it. In this contract the principal provides the means for the education of the child. He appoints teachers to teach him, draws up the educational programme and ensures the child's well-being and development in every way. The child's part in this covenant is to follow the instructions of the teacher and learn every lesson he is taught. It is through this process that the child acquires knowledge, develops his capacity, and becomes endowed with intellectual and spiritual powers. As the child grows in learning and maturity, the principal will appoint other teachers to contribute to his education. In this covenant, the responsibilities of the two parties are fundamentally different. They cannot be confused and are not interchangeable. Another feature of this covenant is that the two parties are not of the same calibre. One side, the school principal, is knowledgeable, wise and strong. The other, the child, is unlearned, weak and immature. The terms of this covenant are drawn up entirely by the strong party and the child has no say in them. Usually, the weaker party is the loser when a contract is drawn up solely by the strong. Not so in this case, for the motive of the principal in making all the arrangements is his love for the child and concern for its education. His greatest ambition is to see the child attain wisdom and knowledge. He longs to see his pupil become a mature person. The same is true of God. He is the Creator, the Almighty, the Author of the Covenant, whose terms He Himself has stipulated unilaterally without the help of man. As in the above example, God's part in this Covenant is different from man's. God's part is to release the vivifying forces of life and of Revelation, and man's is to receive these voluntarily and obey His commandments wholeheartedly.

Adib Taherzadeh, The Covenant of Bahá’u’lláh, p. 1-2