Al-Sahifa al-Sajjadiyya (الصحيفة السجادية) is said to be the oldest prayer manual in Islamic sources and one of the most seminal works of Islamic spirituality of the early period. It is also known as Sahifa-e-Kamila, Sister of the Qur'an, Gospel of the Folk of the House, and Psalms of the Household of Muhammad.
There is multiple versions of al-Sahifa al-Sajjadiyya, one such version transmitted by Zaydi Shi'a sources, differentiating itself from the twelver Shi'a version in that it does not transmit as many supplications as were gradually accepted into the mainstream version. The version authenticated by twelver scholars contains fifty-four main supplications along with the addenda which was interpolated into the text by Shams al-Din Muhammad ibn Makki. Fifteen munajat were also "added to several modern editions of the Sahifa and seem to have been brought to the attention of the main body of Shi'ites by `Allama Muhammad Baqir Majlisi (d. 1110/1689-9 or a year later), author of the monumental compilation of Shi'ite hadith, Bihar al-Anwar." Furthermore, a host of other supplications were later attributed to Zayn al-'Abidin as well and are recorded in separate collections named as the second Sahifa, third Sahifa and so on:
- "The second Sahifa which is about as long as the Sahifa itself, was compiled as the `sister' of the Sahifa by Muhammad ibn al-Hasan al-Hurr al-'Amili (d. 1104/l692-3)"
- "A third Sahifa was put together by the author of Riyad al-'ulama' Mirza 'Abd Allah ibn Mirza `Isa Tabrizi..."
- "The longest of the published versions is Al-Sahifa al-Sajjadiyya al-khamisa (`The Fifth Sahifa of al-Sajjad') by Muhsin al-Amin...It includes all the supplications included in the previous Sahifas; 130 of these are found in the first and second Sahifas and 52 are added."
Shi'as believe that the Sahifa al-Sajjadiyya was composed by Muhammad's great grandson, Ali ibn Husayn (658-713), the fourth of the Shi'a Imams, and has been cherished in Shi'a sources from earliest times. The scholarly Shi'a understanding on authenticating the supplications as summed by S.H.M Jafri is to simply accept the texts as reliable on the basis of their content and to ignore their authenticity in terms of the sources from which the supplications are derived:
- "Any serious attempt to sort out the relative historical reliability of the individual supplications found in all the versions of the Sahifa on the basis of modern critical scholarship would be an undertaking of major proportions. The result of such a study - if one can judge by studies of other ancient texts - would probably be that, after years of toil, we would have a series of hypotheses, leaving varying degrees of doubt. This would be of interest to Western scholars and modernized Muslims, both of whom, in any case, have no personal involvement with the contents and teachings of the Sahifa. But the attitude of most Muslims has been to look at the content of the texts established by the authority of tradition and not be too concerned with who actually wrote the words in `historical fact'.In this regard the saying of 'Ali is well known: `Look at what has been said, not at who has said it', since only the truth or untruth of the words is of real concern. From this point of view, if the author of the Sahifat al-kamila was not Imam Zayn al-'Abidin, he - or they - would in any case have to have been a spiritual authority of equal rank, so the whole exercise leaves us where we started: with a text which expresses the highest aspirations of the Muslim soul."