Also, it would be appropriate to ponder about the narrations regarding supplications, as well as to think about the ways and manners of supplications as practised by the sinless Imams [a]; must take a profound look at the exalted themes and subtle meanings which are contained in the supplications compiled by those honourable ones. In order to discover that whatever these impeccable ones have incorporated in their supplications regarding Allah (the Glorious, the Exalted), His Sacred Names, Characteristics, Glory, and Splendour is far deeper than what could be imagined by human thinking and comprehension. One will discover what sort of beauty and elegance have been shown by them in their etiquette of servanthood; what have been uttered by them regarding the Splendour and Glory of Allah (the Glorious, the Exalted); in what pleasing manners they had asked him for forgiveness and blessings, and by what excuses had pleaded Him for bestowing His love, mercy, benevolence and blessings?
I can swear to my own soul that these exalted themes and sweet pleasing manners of these supplications, are the most explicit manifestation of miracle, proving the authenticity of divine mission of these sinless Imams [a]. And the one who possesses some sense of thinking and some degree of understanding in his heart, if will ponder about these supplications, would certainly accept their vicegerency (Imamat)[20] without requiring any further proof and miracle.
And the one who desires to appreciate more about the splendour, eminence, and sweetness of these supplication should engage himself in supplications; without copying from their supplications should compile his own prayer; then he should compare it with the supplications of those noble ones, in order to discover the limits of variation between his own and theirs.
Yes! The aware and enlightened ones who dare to swim in this fathomless ocean of these supplications and with a penetrating eye ponder about their profundities will discover that what sort of learning and sublime realities, to the extent of miracles have been incorporated in their supplications by the sinless Imams [a]. I myself have not seen even one tenth, rather one hundredth of realities and learning (which have been incorporated in these supplications), in other speeches of those noble ones, even did not find them in narrations and lengthy sermons. (Of course, with the exception of some narrations which deal with communications with Allah, monotheism, praise, and worship).
The mystery of this variation could be that those honourable ones in their narrations had spoken with the people while in their supplications and hymns have spoken with Allah (the Glorious, the Exalted). Obviously, the degree of speech, its culmination, and descent depends upon the degree of intelligence and comprehension of the addressee; the delicate and sensitive points which are spoken before an aware and knowledgeable addressee are not spoken before some one who lacks these characteristics.
Yes! These supplications, reached to us through Sinless Imams of the Prophet's Ahlul-Bait [a] as though form the complete reflection, or echo of whatever is contained in the Holy Qur'an. Or in other words these supplications constitute on Ascending-Qur'an in front of a Descending-Qur'an. The later is the holy scripture which was revealed by Allah (the Glorious, the Exalted), to his esteemed servant - Prophet Muhammad [s], while the former constitutes the Qur'an from Allah's most distinguished servants, ascending upward towards Him. While the Qur'an is Allah's communications and candid words with his esteemed servants; these supplications are a communication of Allah's esteemed servant with Him, and this matter is not accepted and comprehended by any one, except a small number of believers who are thoroughly familiar and enlightened.
Also, it should be emphasized that the sinless Imams [a] through these supplications have done a great favour to us by leaving such precious souvenirs - the souvenirs and blessings, for which we are helpless to thank; it is our obligation to appreciate their worth; in our actions must utilize the etiquette and proper manners as recommended by them; and must try with best of our abilities lest we act as unthankful and unappreciative of truth.
[20] Imamat: The position of leadership in religious and civil matters in the Islamic society is known as the Imamate, and its holder is known as the Imam. It is the belief of Shi'i Muslims that Allah (the Glorious, the Exalted), must have designated an Imam for the people after the death of the Most Noble Messenger [s] to uphold the culture and laws of the religion and to guide people on the way of truth. The term Imam as used in a technical sense in Shi'ism differs from the general usage of the term in Arabic, where it means "leader" or in Sunni political theory where it means the caliph himself. As used technically in Shi'ism the term refers to the person who contains within himself the "Muhammadan Light" which was handed down through Fatimah al-Zahra [a] the daughter of the Blessed Prophet [s], and 'Ali [a], the first Imam, to the others, terminating with the Hidden Imam who is to appear again one day as the Mahdi. As a result of the presence of this light, the Imam is considered to be "Sinless" and to possess perfect knowledge of the esoteric as well as the exoteric order. The Imams are like a chain of light issuing forth from the "Sun of Prophecy" which is their origin, and yet they are never separated from that Sun. Whatever is said by them emanates from the same inviolable treasury of inspired wisdom. Since they are an extension of the inner reality of the Blessed Prophet [s], their words really go back to him. That is why their sayings are seen in the Shi'ite perspective as an extension of the prophetic Hadith, just as the light of their being is seen as a continuation of the prophetic light. In Shi'ite eyes, the temporal separation of the Imams from the Blessed Prophet [s] does not at all affect their essential and inner bond with him or the continuity of the "Prophetic-light" which is the source of his as well as their inspired knowledge [Tr].
source : http://www.al-islam.org