Pact of Brotherhood
Pact of Brotherhood (Arabic: مؤاخاة) is an agreement or pact between two Muslims to the effect that they count as one another's brothers. The pact does not have legal consequences, such as inheritance or their family members being mahram. Therefore, such brothers do not inherit from each other and the family members of one party (such as their mothers or sisters) do not become mahram with the other party.
The best-known pact of brotherhood is the one made by the Prophet (s) between Muhajirun and Ansar, in which he made such a pact between Ali b. Abi Talib (a) and himself. The brotherhood between the Prophet (s) and Imam Ali (a) is reported with tawatur. In addition to Shi'a sources, it has also been reported by Sunni sources—'Allama Amini has cited 50 such reports in Sunni sources in his book, al-Ghadir.
It is supererogatory (mustahab) to make a pact of brotherhood on the Eid al-Ghadir—in this day, people recite vows of brotherhood to the effect that they count as one another's religious brothers (or sisters).
The historical background of the concept of religious brotherhood in the culture of the early Islam is older than the Prophet (s) making pacts of brotherhood between Muhajirun and Ansar after his migration from Mecca to Medina. One of the oldest uses of the notion of brotherhood among Muslims is the one made by Muslims in Mecca about their fellow Muslims in Yathrib (or Medina) before they migrated there. On the other hand, it seems that the notion of religious brotherhood does not have its root in the Jahiliyya culture (that of Arabs before the emergence of Islam); rather it counts as one of the main strategies of the Prophet (s).
Most historiographers maintain that before his migration to Medina, the Prophet (s) made pacts of brotherhood among Muslims in Mecca (who were later called "Muhajirun") so that they assist each other when polytheists bothered them and when they wanted to migrate to Medina. According to historical sources, the Prophet (s) made pacts between pairs of Muslims in Mecca: Abu Bakr and 'Umar, Hamza b. 'Abd al-Muttalib and Zayd b. Haritha, 'Uthman and 'Abd al-Rahman b. 'Awf, al-Zubayr and Ibn Mas'ud, Bilal al-Habashi and 'Ubada b. Haritha, Mus'ab b. 'Umayr and Sa'd b. Abi Waqqas, and many others.
5 or 8 months after the migration of Muslims to Medina, the Prophet (s) told his Sahaba: "every pair of you be brothers in the way of God". There is disagreement among historiographers with respect to the number of Muslims. According to many sources, they were 90 people: 45 from Muhajirun (those who had migrated from Mecca to Medina) and 45 from Ansar (residents of Medina who helped the migrants).
This pact of brotherhood among Muhajirun and Ansar is reported with tawatur with more or less similar phrases. According to sources, the Prophet (s) made pacts of brotherhood for pairs of Muslims (where a pair consisted of a Muslim from Muhajirun and a Muslim from Ansar), such as: Abu Bakr and Kharija b. Zayd al-Ansari, 'Umar and 'Utban b. Malik al-Ansari al-Khazraji, 'Uthman and Aws b. Thabit, Abu 'Ubayda b. al-Jarrah and Sa'd b. Mu'adh, 'Abd al-Rahman b. 'Awf and Sa'd b. Rabi', Talha and Ka'b b. Malik, al-Zubayr and Salama b. Sallam, Salman al-Farsi and Abu l-Darda', 'Ammar b. Yasir and Hudhayfa b. al-Najjar or, on another account, Thabit b. Qays, and many others.
The brotherhood made in the 9th year after Hijra (630-31) was very significant for the relations among Muslims. What was very significant was the generality of this brotherhood; every Muslim was brothers with another Muslim, and this was emphasized by the Ukhuwwa Verse:
إِنَّمَا الْمُؤْمِنُونَ إِخْوَةٌ فَأَصْلِحُوا بَيْنَ أَخَوَيْكُمْ ۚ وَاتَّقُوا اللَّهَ لَعَلَّكُمْ تُرْحَمُونَ
Believers are indeed brothers, so make peace and reconciliation between your two (contending) brothers; and fear Allah, that you may receive mercy.
|— The Qur'an, 49:10|
When the verse was revealed, the Prophet (s) made pacts of brotherhood for pairs of Muslims who were similar to one another in their characters; for example, between Abu Bakr and 'Umar, Abu Dhar and Ibn Mas'ud, Salman al-Farsi and Hudhayfa, Miqdad and 'Ammar b. Yasir, Aisha and Hafsa, Umm Salama and Safiyya bt. Huyyay.
The Prophet's (s) Brotherhood with 'Ali (a)
The pact of brotherhood between the Prophet (s) and Imam 'Ali (a) has been reported with tawatur. In addition to Shiite sources, it has also been reported by many Sunni sources. 'Allama Amini has cited 50 such sources in his book, al-Ghadir.
Before his Hijra (migration from Mecca to Medina), the Prophet (s) made pacts of brotherhood for pairs of Muhajirun. He then made a pact between Imam 'Ali (a) and himself. According to the book, al-Sira al-Halabiyya, "a person went to 'Abd Allah b. 'Umar and asked him about 'Ali (a). Ibn 'Umar said: 'this is the house of the Prophet (s) and this is the house of 'Ali; do you want me to tell you about him?' 'Yes', the man said. Ibn 'Umar said: 'The Prophet (s) made pacts of brotherhood among Muhajirun but 'Ali remained without any pact. He told the Prophet (s): O' the messenger of God, you have made pacts of brotherhood among Muhajirun, but who is my brother? The Prophet (s) told him: are you happy to be my brother in this world and in the afterlife? 'Ali (a) said: Yes. The Prophet (s) responded: so you are my brother in this world and the afterlife.
When Muslims migrated to Medina, the Prophet (s) made pacts of brotherhood between Muhajirun and Ansar, but he did not make Imam 'Ali (a) brothers with any of Ansar. Instead, he himself made a pact of brotherhood with 'Ali. The author of A'yan al-Shia has cited Ibn 'Abd al-Barr in the book, al-Isti'ab, and Ibn Athir in the book, Usd al-ghaba, as reporting that the Prophet (s) made pacts of brotherhood among Muhajirun before their Hijra to Medina, and then in Medina, he made such pacts among Muhajirun and Ansar, but both times, he told 'Ali (a): "You are my brother in this world and in the afterlife", making a pact of brotherhood with 'Ali (a).
According to the book, al-Fusul al-muhimma, when the Prophet (s) made pacts of brotherhood between Muhajirun and Ansar, he did not make 'Ali b. Abi Talib (a) brothers with anyone. 'Ali went left the meeting with sadness. The Prophet (s) looked for him and he then told him: "Are you sad that I have made pacts of brotherhood among Muhajirun and Ansar, but I did not make you brothers with any of them? Are you not happy that your place to me is like that of Aaron (a), to his brother Moses (a) except that there will be no prophets after me?"
Goal of Making Pacts of Brotherhood
One of the main concerns of the Prophet (s) was to establish social justice among all people, and this required, on the one hand, the collapse of social classes, and, on the other hand, an establishment of close relations and affinities among individual people. Thus the Prophet (s) established the relation of religious brotherhood as a practical strategy to form brotherhood and equality among all people.
Before the Ukhuwwa Verse was revealed, it would have been thought that the establishment of religious brotherhood was merely a wise and intelligent strategy by the Prophet (s) as a religious and political leader in order to solidify the foundations of the newly emergent Islamic community and provide spiritual support for it. However, the revelation of the Ukhuwwa Verse showed that such a relation was, in addition to being a political strategy to unify the Islamic nation, part of Islamic doctrines legislated by God.
Pact of Brotherhood in Eid al-Ghadir
It is religiously supererogatory (mustahab) for religious brothers and sisters to make pacts of brotherhood (and sisterhood) among themselves, in Eid al-Ghadir, so that they help each other in this world and in the afterlife.
Such a pact does not generate legal commitments such as inheritance or the family members of each party of the pact being mahram with the other party.
The pact can only be made between two men or two women, and it is not legitimate for a man and a woman to make such a pact between them.
Thus the pact implies that the two parties give each other spiritual helps in this world and after death. For example, they commit themselves to pray for one another and, if possible, to intercede (Shafa'a) for one another.
Procedures of Making a Pact of Brotherhood
Two men or two women shake each other's right hands, with one of them reciting the verbal vow of brotherhood and the other accepting it.
Here is the verbal vow: "For the sake of God, I will be your brother and I will be honest with you, and for the sake of God, I will put my hand in your hand, and before God, His angels, his holy scriptures, and his prophets, I promise that if I deserve to go to the heaven and I am allowed to intercede for you, then I will not enter the heaven without you". 
And then the other party responds: "I accept" (قَبِلْتُ).
Then the first speaker says: "I do not give you any rights of brotherhood except those of intercession, praying, and visits". 
And again the other party responds: "I accept" (قَبِلْتُ).
The verbal vow does not need to be recited in Arabic; it can be recited in any languages, but the words should convey the meanings of this vow.
- «واخَیْتُکَ فِی اللَّهِ وَ صَافَیْتُکَ فِی اللَّهِ وَ صَافَحْتُکَ فِی اللَّهِ وَ عَاهَدْتُ اللَّهَ وَ مَلَائِکَتَهُ وَ کُتُبَهُ وَ رُسُلَهُ وَ أَنْبِیَاءَهُ وَ الْأَئِمَّةَ الْمَعْصُومِینَ (ع) عَلَى أَنِّی إِنْ کُنْتُ مِنْ أَهْلِ الْجَنَّةِ وَ الشَّفَاعَةِ وَ أُذِنَ لِی بِأَنْ أَدْخُلَ الْجَنَّةَ لَا أَدْخُلُهَا إِلَّا وَ أَنْتَ مَعِی»
- «أَسْقَطْتُ عَنْکَ جَمِیعَ حُقُوقِ الْأُخُوَّةِ مَا خَلَا الشَّفَاعَةَ وَ الدُّعَاءَ وَ الزِّیَارَة»
- The material for this article is mainly taken from عقد اخوت in Farsi Wikishia.