Praise be to Allah, and may Allah’s peace and blessings be upon the Messenger of Allah, his family and his companions.
As to what follows:
Brotherhood in its essence is a meaning that has been set for your partner in birth. However, it has become used for every partnership in tribe, profession, religion, trade, friendship, or other than that of meanings and occurrences. But since brotherhood in religion is the strongest of these bonds and ties, Allah Almighty made it restricted to the believers besides everyone else. He said:
“The believers are but brothers, so make reconciliation between your brothers. And fear Allah that you may receive mercy.” [Al-Hujurat 49:10]
Imam al-Shafi`i (may Allah have mercy on him) said, “He made brotherhood to be between the believers, and cut it off between the believers and disbelievers.” [Al-Umm 6/40]
This brotherhood is not established except for the People of Iman. Allah Almighty said:
“But if they repent, establish prayer, and give zakah, then they are your brothers in religion; and We detail the verses for a people who know.” [Al-Tawbah 9:11]
Shaykh al-Islam Ibn Taymiyyah said, “So He conditioned brotherhood in religion to repentance from shirk, establishing prayer and giving zakah; and one thing that is conditioned to another ceases to exist when its condition ceases to exist. So whoever does not do any of that is not a brother in religion, and whoever is not a brother in religion is a disbeliever.” [Sharh al-`Umdah, p. 73]
As for what has been mentioned concerning attribution of brotherhood to a non-Muslim, like in Allah Almighty’s statement:
“And to `Aad, [We sent] their brother Hud.” [Al-A`raf 7:65]
And His statement:
“And to Thamud, [We sent] their brother Salih.” [Al-A`raf 7:73]
And His statement:
“And to Madyan, [We sent] their brother Shu`ayb.” [Al-A`raf 7:85]
…and other similar verses, then it is either brotherhood in blood or cause [such as through breastfeeding]. Moreover, it has been mentioned in the context of relaying information, not of forming a ruling; as opposed to the brotherhood of Iman, for Allah and his Messenger have made rulings and rights to result from it, such as in Allah’s statement:
“The believers are but brothers, so make reconciliation between your brothers. And fear Allah that you may receive mercy.” [Al-Hujurat 49:10]
And as has been mentioned by `Abdullah bin `Umar (may Allah be pleased with him), that the Messenger of Allah (peace be upon him) said, “A Muslim is a brother of another Muslim. So he should not oppress him nor should he hand him over [to an oppressor]. Whoever fulfills the needs of his brother, Allah will fulfill his needs.” [Bukhari (6591) and Muslim (2568)]
And other similar texts.
So what I opine is that it is impermissible to generalize the usage of brotherhood to include the disbelievers, because Allah Almighty has cut that off between the believers and disbelievers, and because there is deception in this generalization that leads to disruption of rulings, mixing of rights and weakening of the brotherhood of Iman.
However, if the generalization of brotherhood is restricted to blood or cause, and that becomes apparent beyond a doubt, as has been mentioned in the above verses, then there is no problem in generalizing it in that case due to its clarity and distinctness from the brotherhood of religion and what it necessitates of rights and obligations. Likewise, the same ruling applies where the intent is merely calling someone [by saying, “O brother”], as some people use it. At any rate, what is obligatory is to be on the safe side in circumstances that are doubtful.
As for generalization of the usage of brotherhood to include the Jews, Christians and others, basing it on brotherhood in humanity, then this is something that no one with knowledge of Islamic law and comprehension of what such statements lead to would doubt its impermissibility; for the pure Islamic legislation has not given any special consideration for this bond and tie, even though its circumstances existed in the time of legislation; rather, its address was general for Muslims and disbelievers alike, saying, “O mankind,” or, “O son of Adam.” Also, regardless of how much one may search the compilations and books of Islam, in the various disciplines, from tafsir to hadith to fiqh and others, he will never succeed in bringing out one word from anyone among the scholars and Imams of the religion to rely upon in generalizing brotherhood to include the disbelievers based on brotherhood in humanity.
Among that which proves the prohibition of generally calling disbelievers brothers of Muslims is that it leads to equating between those whom Allah has separated, such as Allah Almighty’s statement:
“Or should we treat those who believe and do righteous deeds like corrupters in the land? Or should We treat those who fear Allah like the wicked?” [Sad 38:28]
And His statement:
“Or do those who commit evil deeds think We will make them like those who believe and do righteous deeds - [make them] equal in their present life and after their death? Evil is that which they judge.” [Al-Jathiyah 45:21]
What further emphasizes the prohibition of generally calling disbelievers brothers of Muslims is that the promoters of causing corruption and evil have made the call for brotherhood in humanity as a means and stepping-stone to belittling the issue of kufr (disbelief) and accepting its people, loving them and allying with them. They have also taken it as a tool to promote many deviant ideologies and dubious projects. Among the principles that is agreed upon by scholars of Islam is that whatever is a means to a prohibition is itself a prohibition. So how about when all of it is prohibited?
In conclusion, it is worth noting that cutting off brotherhood between the believers and disbelievers does not result in doing away with, nor justify violating, the rights of innocent disbelievers; for their rights are preserved and their sanctities are protected, as long as they have the protection of Islam by custody, pact, or security.
And Allah knows best.
Your brother,
Khalid bin `Abdullah al-Muslih
3 / 1 / 1425 AH