To describe the depth of brotherhood in Islam (ukhuwah Islamiyah), Allah SWT uses the word ikhwah, which means "siblings" (Qur'an 49: 10). This is different from the Brotherhood, which means "friends". As used by Allah in the letter of Ali 'Imran: 103, to describe how the Arab tribes in the Jahiliyah era were originally enemies, then united after embracing Islam.
So, after being in one religion, every Muslim is a friend to another. And after Islam has increased, every Muslim should be able to view other Muslims as his siblings.
Ukhuwah Islamiyah can be realized (as said by the Prophet) among others in the form that a Muslim must be able to love other Muslims as he loves himself; that a Muslim must be able to feel the difficulties experienced by other Muslims, as pain in one limb is felt by all other members of the body; that a Muslim must support one another, as one part of the building supports another.
In the Koran, Allah SWT requested that a Muslim not be hostile, berate, mock, and be detrimental to other Muslims (Qur'an 49: 9-12). What needs to be developed is precisely the attitude of mutual forgiveness (Qur'an 24: 22). Even fellow Muslims need to pray for one another (QS. 3: 159) and awliya ', protect-protect (Qur'an 9: 71).
We should not be like the infidels who took Taghut as a protector, because they fought for the evil of evil (Surah 2: 257 and 4: 76). And we should not be like hypocrites who support each other precisely in advocating the evil, forbidding the righteous, miserly, and not heeding God (Qur'an 9: 67).
The Islamic Brotherhood requires a tangible manifestation, namely a minimum of sacrifice in property. "If they repent, establish prayers, and pay zakat, then they are your friends as religionists," said Allah SWT (Qur'an 9: 11). What must be issued is not only zakat, but also infaq (QS. 2: 195), which is a financial obligation whose amount is contained in the willingness (faith) of contributors.
The manifestation of brotherhood in Islam even to the willingness to sacrifice lives. Allah said, "How can you not fight in the way of Allah for the oppressed (men, women, and children) who exclaim, 'O our Lord, remove us from this city, whose inhabitants do wrong. Give us protection from you. And give us defenders. ”(Qur'an 4: 75).