One of the important disciplines of reciting the Divine Book, shared by the gnostic and the common man, and which brings about good results causing luminosity for the heart and the interior life, is to regard it with "reverence", which depends on realizing its greatness and majesty. This, however, is, actually, out of the scope of explanation and beyond the human capacity, because understanding the greatness of a thing depends on understanding its truth, while the truth of the Divine Holy Qur'an, before being sent down to the stages [manazil] of creation and before undergoing practical modes [atwar], is of the affairs [shu'un] of His Essence and of the facts of Knowledge in His Unity [hadrat-i wahidiyat]. It is the truth of a "Self-speech" [kalam-i nafs], which is the "Essential Argument" [muqari`a-i dhatiyah] in His Names. This truth appears to no one, neither by means of formal sciences or cordial knowledge nor by unseen disclosure, except through complete divine revelation to the blessed person of the Final Prophet (SA), in the intimacy of qaba qausayn [at the distance of two bows' length], or even in the secret privacy of au adna [or nearer]. The hand of hope of the human species is short of that, except, that of the sincere of Allah's friends who, according to the spiritual lights and the divine facts, share in the spirituality of the Prophet's sacred essence and, through their complete subordination, they vanished in him. They receive the disclosing knowledge by inheriting it from him, and the truth of the Qur'an may be reflected in their hearts, with the same luminosity and perfection with which it appeared in the heart of that great personality, without its descending to [mundane] stations and taking [mundane] forms. That Qur'an is without change and alteration, and it is of the book of divine revelation. The one capable of carrying this Qur'an is the noble person of the absolute friend of Allah, 'Ali ibn Abi Talib (AS). Others cannot take this fact in, unless it descends from the station of ghayb [the invisible] to the station of visibility and takes the seen form, wearing the apparel of mundane words and letters. This is one of the meanings of "changing" [tahrif] or alteration which has occurred in all Divine Scriptures as well as the Qur'an, changing all the noble ayahs, which, with a change, or rather many changes, according to the stations and stages which continue from His "Names" to the last of the worlds of vision and visibility, are placed within the reach of man. The number of the stages of the change corresponds to the number of the stages of the butun of the Qur'an exactly. The meaning of the change [tahrif] here is the descent from absolute ghayb to absolute visibility, in accordance with the degrees of the worlds, whereas the butun is the return from absolute visibility to absolute ghayb. So, the beginning of the change, and the beginning of the butun are opposed. Whenever a salik attains to a stage of the butun, he gets rid of a degree of the change. When he arrives at the absolute butun, which is the seventh, according to the general classification, he absolutely gets rid of the change [tahrif]. So, it maybe that the Qur'an appears to some to be full of different changes. To another, it may appear with few changes, while to a third it appears with no change at all. It may also appear to somebody changed in some instances and unchanged in some others, or with some sorts of changes in a third instance.
As you know, understanding the greatness of the Qur'an is beyond the capacity of the intellect. Yet, a general hint at the greatness of this Divine Book, which is within the reach of everybody, is of many advantages.
Do know, dear, that the greatness of a speech or a book is derived from the greatness of the speaker and the writer, from the greatness of its contents and objectives, from the greatness of its results and fruits, from the greatness of its intermediate conveyer, from the greatness of its receiver and its carrier, from the greatness of its keeper and protector, from the greatness of its commentator and explainer or from the greatness of the time of its being sent down and how it was sent. Some of these, however, are by nature the causes of greatness, others are indirectly so, and some are proofs of the greatness. All the said matters are contained in this luminous Book in their very best and satisfaction, or, actually they are its distinguished characteristics. No other book shares them with it, or covers all of them comprehensively.
As regards the greatness of the speaker, the composer and its owner, He is the Absolute Great, for all kinds of greatness that can be imagined on the earth and in the heavens, and all powers descending in the visible and the invisible, are but a seepage of the manifestations of the greatness of the act of His Sacred Essence. Allah, the Exalted, would not show Himself to anybody through manifesting His Greatness from behind thousands of veils and curtains, as a hadith says: "Allah has seventy-thousand veils [of light and darkness, if removed away, the lights of His Face would burn everything other than Him.] "  To the people of knowledge, this noble Book has issued from Allah, the Exalted, the Origin of all affairs of the Essence, Attributes and Acts, and of all manifestations of Beauty and Majesty. The other divine Books do not enjoy a similar status and position.
As regards the greatness of the contents, objectives and subjects, it requires a separate chapter, or, say separate chapters, sections, a thesis or a book, so that one may relate only a part of that. We shall, nevertheless, generally refer, in a separate chapter, to its universal principles. In the said chapter we shall point out, insha'allah, its greatness in respect of its results and outcome.
As regards the greatness of the messenger and the conveyer of its revelation, he is the Faithful Gabriel, the Great Spirit. After that the noble Messenger of Allah (SA) had quitted the apparel of the nature of the flesh and directed the heart towards His Majesty, he got in touch with that Great Spirit. He is one of the four pillars of the House of Realization, or rather he is the greatest of its pillars and the most honourable of them, since that noble and luminous Archangel is the guardian of knowledge and wisdom, and the conveyer of the spiritual provisions and moral nourishments. From the Book of Allah and the noble hadiths one realizes the greatness of Gabriel and his preference to other angels. 
As regards the greatness of its receiver and carrier, it is the pure and pious, Ahmadan single [ahmadi-i ahadi], Muhammadan collective [jam`i-i muhammadi] heart, to which Allah, the Exalted, appeared in all affairs [shu'un] of the Essence, Attributes, Names and Acts. He [the Prophet] is the Seal of prophethood and the absolute guardian, the most generous of all creation, the best of the human beings, the gist [khulasah] of the universe, the essence [jauharah] of existence, the substance [`usarah] of the House of Realization, the last brick and the owner of the big isthmus and great vicegerency [khilafat].
As regards the greatness of its keeper and guardian, He is the Sacred Essence of Allah, the Exalted as He says in the noble ayah: "It is We Who have sent down the Reminder [ the Qur'an] , and verily We are its keeper." 
As regards its commentators and explainers, they are the pure infallible ones-beginning with the Messenger of Allah and ending with "the Proof of the Time" [hujjat-i `asr], may Allah enhance his rise-who are the keys of existence, the deposits of dignity, the sources of wisdom and inspiration, the origins of knowledge and learning, and the possessors of the state of collectivity [jam'] and distinctness [tafsil].
As regards the time of revelation, it is laylatul Qadr [The night of the qadr], which is the greatest of nights and "better than a thousand months". It is the most luminous of times. In fact, it is the time of the attainment [wusul] of the General Guardian [waly-i mutlaq] and the Seal of the Prophets (SA).
As regards how it was revealed and its relevant ceremonies, they are beyond the limits of the capacity of these few papers. They require a special chapter, which, owing to its elaboration, will have to be omitted.
. Biharul Anwar, vol. 55, p. 45. This hadith is (also) related by the Sunni sources.
. Look up Surahs ash-Shu'ara: 193, an-Najm: 5-9 and at-Takwir: 19-24. Also Biharul Anwar, vol. 56, p. 258, "Book of the Heaven and the World", chs. on "The Angels" and "Another Chapter on Describing the Favourable Angels", hadith 23 and 24.
. Surah al-Hijr: 9.