Muharram 2, 1320
1) Yes, indeed, I would like to recite unto you one of the perfect verses of Allah, the Exalted, the Almighty, in His great Book which distinguishes right from wrong. It is one of the verses of Surat al Ma'ida (Table of Viands):
Only Allah is your wali and His Messenger and those who believe, those who say their prayers and offer zakat (even) while prostrating (in prayers). And whoever takes for wali Allah, His Messenger, and the believers, they, indeed, are the party of Allah; they are the ones who shall achieve victory.
Nobody doubts the fact that these verses were revealed in honour of `Ali who offered his own ring in the way of Allah while engaged in performing the prayers.
2) The sahih books consecutively report, through the authority of the Imams from among the Purified Progeny, stating that it was revealed in honour of `Ali when he, out of charity, offered his ring while prostrating in prayers. Refer to what has been said in this regard by others such as Ibn Salam who quotes hadith from the Prophet, peace be upon him and his progeny. Refer to it as published in Nisa'i's Sahih, or in Al-Jami Bayna al-Sihah al-Sittah, in a chapter dealing with the interpretation of Surat al Ma'ida. Likewise, refer to the hadith of Ibn `Abbas who explains the meanings of these verses in imam al-Wahidi's book Asbab al-Nuzul. Al-Khatib has included it in Al-Muttafaq. Also refer to `Ali's hadith in the musnads of Ibn Mardawayh and Abul-Shaykh. If you wish, refer to it in Kanz al-`Ummal.
Its revelation to honour `Ali is a matter of consensus among scholars of the exegesis of the Holy Qur'an. Such consensus is attested to by many Sunni scholars like Imam al-Qawshaji in his chapter on imamate in Sharh al Tajrid. Chapter 18 of Ghayat al-Maram includes one hadith narrated through the Sunnis testifying to our claim. Had I not aspired to be brief, in addition to the fact that this issue is as clear as the sun in midday, I would have quoted for you many comments thereupon in authentic chronicles, but, praise to Allah, it is a matter which does not entertain any doubt. Despite that, we do not like to let this letter be without a few ahadith narrated by the majority of Muslims.
Suffices us what Imam Abu Ishaq Ahmed ibn Ibrahim al-Nisaburi al-Tha`labi has stated in his Al-Tafsir al-Kabir. When the writer comes to this verse, he quotes Abu Tharr al-Ghifari saying:
"I have heard the Messenger of Allah, peace be upon him and his progeny, with these ears - may I be deaf if I tell a lie - and saw him with these eyes - may I be blinded if I lie - saying: `Ali is the leader of the pious, the annihilator of infidels; whoever supports him is supported by Allah, and whoever abandons him is abandoned by Allah.' I have, indeed, said my prayers once in the company of the Messenger of Allah, peace be upon him and his progeny, when a beggar came to the mosque and nobody gave him anything. `Ali was in the state of ceremonial prostration when he beckoned to him to take his ring. The beggar came and took it from `Ali's finger, whereupon the Messenger of Allah, peace be upon him and his progeny, invoked Allah, the Almighty, the Omniscient, and prayed Him on behalf of `Ali saying: `Lord! My Brother Moses had prayed to you saying: Lord! Remove the distress from my bosom, render my mission easy for me, and untie my tongue's knot so that people may understand me, and let me have a vizier from my own kin, my brother Aaron, to support my endeavour and participate in my undertaking, so that we may both praise you a great deal and mention your Name a great deal; You have been most Kind unto us (Qur'an, 20:25-35);-thereupon, You inspired to him: Verily, your prayer has been granted, O Moses! (Qur'an, 20:36). Lord! I am Your servant and Prophet; therefore, remove my distress, render my mission easy for me, and grant me a vizier from my kin, `Ali, to support my endeavour'. By Allah, the Messenger of Allah, peace be upon him and his progeny, had hardly finished his supplication before Gabriel, the trusted one, brought him this verse: `Only Allah is your wali and His Messenger and those who believe, those who say their prayers and offer zakat (even) while prostrating (in prayers). And whoever takes for wali Allah, His Messenger, and the believers, they, indeed, are the party of Allah; they are the ones who shall achieve victory (Qur'an, 5:55-56).'"
3) You, may Allah support righteousness through your own person, know that the meaning of the word "wali" in such a context is "one who has the top priority in faring with one's affairs." We say "Such and such is the minor's wali." Lexicographers have made it clear that whoever takes charge of someone's affairs is the latter's wali. The meaning of the verse, therefore, is as though Allah says that "the ones who take charge of your affairs and have priority even over your own lives in faring with the latter are: Allah, the Almighty and Omniscient, His Messenger, and `Ali," for in `Ali alone have all these qualities been combined: faith, saying the prayers, and offering zakat even while prostrating in prayers, and for whom these verses were thus revealed. The Almighty has in these verses reserved wilayat for Himself and for both His Messenger and wasi in the same manner. The wilayat of Allah, the Almighty and Omniscient, is general and inclusive. So is the wilayat of the Prophet as well as his wali; it carries the same meaning. It is not possible to apply to it in this context the meanings of "supporter, loved one, etc.," since such a restriction [of application] is groundless, as is quite obvious. I believe this is a quite clear matter, and praise to Allah, Lord of the Worlds.
 This is why people in Syria call a Shi`ah "mutawali," due to his taking for mawla Allah, His Messenger, and those who have truly believed, that is, those in whose honour the same verse was revealed. Linguistically, the "mutawali" is singular, and the "mutawla" are the Shi`ahs. They are so-called because they accepted the wilayat of `Ali and Ahl al-Bayt (as).
 It is hadith number 5991 of the ones cited in Kanz al-`Ummal on page 391, Vol. 6.
 He died in 337. Ibn Khallikan mentions him in his Wafiyyat al-A`yan saying: "He was the unique authority of his time in the science of exegesis; he wrote Al-Tafsir al-Kabir, which surpassed all other books of tafsir," and he goes on to say: "He is mentioned by `Abdul-Ghafir ibn Isma`il al-Farisi in his book Siyaq Nisabur, where the author lauds him and describes him as `accurate in transmitting, trustworthy.'"