The word du’a (supplication) literally means “to call”, “to request a favour”, “to seek help” and in some cases it is used to denote the general meaning of calling. But in its [popular and] technical sense, it refers to the act of making a request from Allah (awj). The word du’a and its derivatives have been used in the Qur`an in approximately thirteen different meanings.
As supplication is a form of worship, it has like all other forms of worship certain requirements, the fulfilment of which makes the supplication effective in that Allah (awj) grants the supplicant’s request and elevates him to higher stations of proximity to Himself.
It is important to note that the acceptance of supplication does not mean that the request will be instantaneously granted, and that its consequences will become immediately manifest. Hence, in some cases, the result of the acceptance might appear after some forty years, or in yet other cases Allah (awj) may postpone the granting of the request for the hereafter, wherein He will bestow on the supplicant blessings many times greater than what he had asked for, and this experience will so overwhelm the blessed believer that at that moment he will wish that none of his other requests had been granted in the world.
Scholars of Islamic sciences have extracted from the Qur`an and the ahadith of the Infallibles (ع) certain conditions which, if respected, will guarantee the acceptance of the supplication. Mulla Muhsin Fayd Kashani enumerates ten such requirements. Ten other requirements have been recorded in ‘Uddatul Da’i, while seventeen conditions have been put forth in Du’aha Wa Tahlilat-i-Qur`an.
By studying the various phrases that are recorded in the ahadith relating to this topic, it is possible to formulate the conditions that guarantee the acceptance of one’s supplications, such as: not asking for a request that is in contradiction with the “best universal order” that governs the world; the immutable Divine will (in which case the supplication will be disregarded); beginning and ending the supplication with blessings upon Prophet Muhammad and his household (ع); possessing a thorough knowledge of Allah (awj), putting our trust only in Allah (awj) and no other but Him; being sincere and feeling desperately in need of Allah (awj); the harmoniousness of one’s heart and tongue in supplicating; being disposed to carry out our duties and refrain from committing what Allah (awj) has forbidden; pleading for forgiveness of one’s sins; being persistent in beseeching Allah (awj) without loosing hope; knowing that Allah (awj) hears His servants and heeds their supplications; asking Allah (awj) to take care of one’s needs the way He deems appropriate and in accordance with what is best for him, [not what he himself whimsically desires]. If all these conditions are met, the supplicant should have no doubt that the request will be granted, although it be at a later time.
Before venturing to answer the question, the meaning of du’a and the reason for its necessity from the perspective of the Qur`an will be examined briefly.
The necessity of supplication is not an issue confined to Islam; it was also a given among the religions of the ancient prophets, and thus they informed their people regarding this issue. Moreover, there are many instances where the supplications of the ancient prophets have been recorded, one of which is Ibrahim’s (ع) supplication and its acceptance recounted in Surat Ibrahim, verse 37. Another instance is Musa’ supplication related in Surat Taha, verses 25-28. Allah (awj) in many verses exhorts the believers to supplicate Him (See, among others 2:186 and 40:60).
The literal meaning of du’a (supplication) is “calling”, “asking a request”, and “pleading for help.” Although in some contexts it denotes merely “calling.”
In its religious usage however, it refers to asking a favour from Allah, the Exalted. The word du’a and its derivatives that appear in the Qur`an hold approximately thirteen different meanings, some of which are: “calling”, “supplicating”, “asking Allah”, “hollering for someone”, “to invite to a cause or to someone”, “pleading for help”, “worship”, etc.
From some verses and ahadith, it can be inferred that supplication is a form of worship of Allah (awj). Furthermore, in some ahadith, we come across phrases like “Supplication is the core of worship.” In this light, it becomes clear that supplication, like all other forms of worship, has certain positive and negative conditions. In other words, in order for a supplication to be valid and complete and therefore conducive to Divine proximity, the supplicant must furnish certain prerequisites and conform to certain manners and pay heed to certain obstacles. It is after realizing these conditions that it becomes clear why some supplications are not accepted. For Allah (awj) is most wise and knowledgeable and, as such, all His actions are based on wise and reasonable grounds, and thus His granting a request is contingent on whether or not it is conducive to the well-being of the supplicant.
To better understand this; let us imagine a generous and benevolent individual who tells people that he will grant any request that is made to him. Now, if someone approaches him and asks him for something that is detrimental to the his own well-being or something that will entail his certain destruction—wrongly thinking that it is advantageous to him—in such a case, it is obvious that the appropriate response on the part of the generous and benevolent individual should be the rejection of the request. On the contrary, to grant the request in question would be an act of oppression against the requester [in spite of the latter’s feelings]. And it should be noted that most of the requests that human beings make to Allah (awj) are harmful for and disadvantageous to them.
This has been expressed in a sacred hadith; it reads, “There are those amongst My servants for whom only wealth is suitable [as opposed to poverty], and were I to consign them to anything else, they would have certainly perished. And indeed there are those amongst my servants for whom only poverty is suitable, and were I to consign them to anything else, they would have indeed perished.”
At this point, a question might arise in the reader’s mind: Considering the fact that Allah (awj) knows what is good for us better than anyone else and that He will carry out what He wishes, so what need is there for supplication, to request something from Allah (awj)? In reply, it suffices to say that some of the Divine existential decrees (muqaddarat) are contingent on the supplication of the servant. That is, if the servant supplicates, that will be grounds on which the Divine will would allow the bestowal of the request, and if the servant does not supplicate, that ground would be lacking, and hence the request would not be granted. For instance, if one beseeches Allah (awj) to grant him eternal life, Allah (awj) will not accept such supplication, for it contradicts the Divine will as made clear in the Qur`an (3:185); or if one asks Allah (awj) to prevent him from ever being in need of anyone else, such a request would also be denied. It has been narrated that one day Imam ‘Ali b. Abi Talib (ع) overheard someone telling his friend, “May Allah never afflict you with any tribulation or mishap.” On hearing this, Imam ‘Ali b. Abi Talib (ع) addressed the person and said, “You just asked Allah for your friend’s death.” That is, as long as one is alive, one will be afflicted with tribulations and hardships.
In commenting on a hadith, ‘Allama Majlisi forwards some justifications as to why some supplications are not accepted:
1. Allah’s (awj) promise to grant the requests made to Him is conditioned on whether they are in accord with His will, for Allah (awj) says, He will remove that for which you supplicated Him, if He wished (6:41).
2. What is meant by “replying” in the hadith is the concomitant meaning; that is, to hear the supplication of the servant. Allah (awj) accepts the supplication right away but postpones granting the supplicant’s request so that the latter would continue in his supplication, for the believer is the beloved of Allah (awj) and He loves to hear His beloved.
3. Allah (awj) grants only those requests that are to the advantage of the supplicant, for Allah (awj) is wise and as such does not jeopardize what is advantageous to His servant and conducive to his felicity in trying to meet the whimsical wishes of His servant which are in actuality detrimental to his well-being. Thus it becomes clear that when such a promise (to grant the requests of those who beseech Him) is made by a wise being, it must be understood as to pertain only to those requests that are to the supplicant’s advantage.
In Usul al-Kafi, four possibilities have been provided regarding the meaning of “reply” [i.e. Allah’s reply to His servants’ supplications]:
1. Allah (awj) grants the supplicant’s request right away;
2. Allah (awj) accepts the supplicant’s request but postpones granting it for some time, as He likes to hear the voice of the supplicant;
3. Allah (awj) accepts the supplication but fulfils it not by granting what the supplicant had asked for but by erasing the supplicant’s sins, placing it as compensation for his wrongs;
4. Allah (awj) accepts the supplication but fulfils it not by granting what the supplicant had asked for but by reserving it for the supplicant as provision for the hereafter.
In some cases Allah’s (awj) acceptance of the supplication is by way of bestowing on the supplicant several times more than what he had asked for in the hereafter as he was not aware of what was really in his good, and so when he beholds what bounties Allah (awj) has granted him in lieu of what he had asked for, he will wish that none of his requests had been granted and at that point he will confirm that his supplications have been fully accepted.
Up to here, the meaning of du’a and its importance have been illustrated. The conditions of the acceptance of supplication and why some supplications are not accepted were also analyzed. Now it is time to consider the question: under what circumstances are supplications accepted? Scholars of Islam and Qur`anic exegetes have, based on their understanding of the Qur`an and the ahadith, enumerated certain conditions for the supplication and the supplicant, which if observed would render the supplication effectual and thus the request would be granted.
In Du’aha Wa Tahlilat-i Qur`an, the author mentions seventeen conditions for supplication and the manners according to which it should be carried out, some of which are: knowledge of Allah (awj); the concordance of the supplicant’s heart and tongue; carrying out the obligatory duties and refraining from the forbidden acts; repentance; uttering the formula of blessings upon the Prophet and his household, etc.
Mulla Muhsin Fayd Kashani also provides ten conditions in Mahajjah al-Bayda’, in addition to the ten that he quotes from Ahmad ibn Fahd al-Hilli’s ‘Uddatul Da’i. They are, among others: determination in supplication; supplicating as a group; supplicating with a real devotion of the heart [and not perfunctorily]; relying solely on Allah (awj) in one’s needs, etc.
In the ahadith regarding the guaranteed acceptance of supplications, there are some phrases whose mention is not without benefit.
Imam Ja’far b. Muhammad as-Sadiq (ع) says, “Supplications are always behind veils that bar them from reaching the Divine Throne unless they are accompanied by blessings to the Prophet and his household.”
It is narrated in another account that Imam Ja’far b. Muhammad as-Sadiq (ع) said, “Whenever any of you decides to supplicate his Lord, he should commence it by blessing the Prophet, for such a blessing is accepted before Allah and certainly Allah is not such that He would accept part of the supplication while rejecting the rest.”
And yet in another narration, it is recommended that the supplicant bless the Prophet at the close of his supplication as well as at the commencement.
Imam Hasan b. ‘Ali al-Mujtaba (ع) says, “If a person is vigilant to prevent temptations and thoughts that are displeasing to Allah from entering his heart, I will guarantee that he would be mustajab al-da’wah [i.e. that Allah will grant all his requests indiscriminately].
Imam Ja’far b. Muhammad as-Sadiq (ع) has been related as having said, “Sever all ties of hope from other-than-Allah until it [i.e. your hope] relies on no other power but Allah, then supplicate, for then surely it will be accepted.”
Also, it has been narrated that the supplication of the oppressed, who has no other refuge but Allah (awj), is certainly accepted.
Thus if the supplication is made in the tone of seeking help, the supplicant will not be repelled and his request will be granted. For, the Agent Who overlooks the affairs of the creatures and He Who grants the requests is perfect and beyond perfect, and His blessings are also perfect and beyond perfect, and so if the blessing is not manifest and does not affect the creatures, it is due to the defective capacity of the receptacle. Thus if the recipient be capable of receiving the blessings, which gush forth from an endless reservoir that never shows any sign of scarcity, the infinitely abundant and rich mines of Divine grace will pour down on him.
Hence, it has been said that human affairs are of three types: one type are those which are willed by Allah without any need for supplication, in which case whether or not the recipient supplicates, he will receive what has been allocated for him; the next type are those which will not be willed by Allah (awj) regardless of whether or not the individual supplicates, in which case even if the individual supplicates his request would not be granted; the third group are those which Allah (awj) wills, provided the beneficiary supplicates, and as such Allah (awj) will not will it without the beneficiary’s supplication. In the latter case, Allah’s (awj) granting the request is contingent on the supplication of the beneficiary, and as the human being is ignorant of the advantageousness or disadvantageousness of what he desires, he must not fail to supplicate for all he wants. Although, he must not be disappointed if it is not granted, for he should know that it was not to his benefit.
Moreover, as mentioned earlier, supplication is a form of worship, rather it is of the best forms of worship, and as such, is very effective in gaining proximity to Allah (awj), which is of the most valuable achievements that can be sought through worship [and thus the supplicant should not be so much concerned as to whether his request is granted or not].
After raising one’s hands in supplication, it is recommended, according to the ahadith and the traditions of the Infallibles (ع), that he rub his hands on his face, for Allah’s (awj) grace has replied to those hands [although it might appear that the supplicant’s request has not been granted]. The hands which have been extended toward Allah (awj) in supplication will definitely be blessed and so the supplicant will not terminate his supplication empty handed, and the hands that have been blessed by Allah (awj) are sacred. Thus, it is recommended that the supplicant rub his hands on his face.
 al-Kafi, vol. 2, pg. 352:
وَإِنَّ مِنْ عِبَادِیَ الْمُؤْمِنِینَ مَنْ لاَ یُصْلِحُهُ إِلاَّ الْغِنَى وَلَوْ صَرَّفْتَهُ إِلى غَیْرَ ذٌلِکَ لَهَلَکَ، وَإِنَّ مِنْ عِبَادِیَ الْمُؤْمِنِینَ مَنْ لاَ یُصْلِحُهُ إِلاَّ الْفَقْرَ وَلَوْ صَرَّفْتَهُ إِلى غَیْرَ ذٌلِکَ لَهَلَکَ.
 Mir’at al-’Uqul,vol. 12 pg. 19-20
 al-Kafi, vol. 1, pg. 330
 Mir’at al-’Uqul, vol. 12 pg. 1-5
 al-Kafi, vol. 2, pg. 491
 Amali, Shaykh Saduq, vol. 1, pg. 157
 al-Kafi, vol. 2, pg. 67
 Bihar al-Anwar, vol. 72, pg. 107