There are different forms of brotherhood in Islam, just as there are various forms of unity in Islam. The first form of brotherhood is familial brotherhood like two brothers or two sisters. Or any two people who are related through their mothers and fathers, they are all sisters and brothers. The second form of brotherhood has to do with nursing. If two infants who do not have familial relations breastfeed from one woman for a specified time, with the conditions that are mentioned in jurisprudence, they will become brother and sister, two brothers, or two sisters due to suckling. When the people whom it is forbidden to marry are mentioned in the Qur''''an, the following phrase is mentioned: ... your [foster-]mothers who have suckled you and your sisters through fosterage ... (4:23) This means that the mothers who nursed you are forbidden to marry just as it is forbidden to marry your natural mothers. Your sisters due to suckling [from the same woman] are also forbidden to marry. This is also another form of brotherhood which is different than familial brotherhood. The third form of brotherhood is tribal brotherhood. Two people from the same tribe are considered brothers, though it may seem strange. In fact, the Qur''''an states that the prophets are brothers of their nations. There are many verses in the Qur''''an which prove this matter: And mention [Hud] the brother of ''''Ad, when he warned his people at Ahqaf. (46:21) And to Midian We sent Shu''''ayb, their brother. (29:36) Certainly We sent to Thamud Salih, their brother. (27:45) Hold fast, all together, to Allah''''s cord, and do not be divided [into sects]. And remember Allah''''s blessing upon you when you were enemies, then He brought your hearts together, so you bee brothers with His blessing ... (3:103) Therefore, this verse considers brotherhood and compassion between believers a blessing from Allah. It states that the divine rope should be clung to. How is brotherhood achieved? The above-mentioned verse is with the compassion in hearts - Remember ` Allah''''s blessing when you were enemies, then He brought your hearts together`, so bringing together of the hearts is a divine blessing. When the Qur’an mentions the issue of unity amongst Muslims (Islamic unity), Islamic brotherhood is also mentioned. It is understood then the Islamic Ummah is truly a single Islamic Ummah when the following conditions are adhered to: First that the religion of Allah and the Qur''''an are held onto: ''''Hold fast to Allah''''s cord’ and second, that the hearts are brought together and Muslims truly consider each other as their Muslim brothers. If one does not think about other Muslims then he is really not part of the Islamic Ummah. In another place, the fondness for religion and holding fast to it is described in the following way: ... But Allah has endeared faith to you and made it appealing in your hearts, and He has made hateful to you faithlessness, transgression and disobedience ... (49:7) This is what is meant by holding fast to religion, but the verses which clearly mention the issues of compassion are verses 62-63 of Surah Infal: `It is He who strengthened you with His help and with the means of the faithfull` (8:62) The Qur''''an then immediately speaks about the believers: `and [God] united their hearts, and if you spent all that is in the earth, you could not have united their hearts ...` (8:63) As example to this we can mention that it was not humanly possible to place compassion between the hearts of the Aws and the Khazraj, who had fought for 120 years. The same could be said for the Quraysh and other Arab tribes who had fought for years. There was no possibility to place compassion between their hearts even through the use of monetary means or worldly blessings. `... but Allah united them together. Indeed He is all-mighty, all wise`. (8:63) By these verses it is understood that this compassion is a divine blessing which is only achieved through a strong belief. Literal meaning of brotherhood Shaykh Tusi defines the Arabic term akh (''''brother'''') in Tibyan. He states that the term akh is used when two or more people have the same destination. He says: yaquluna fulanun yatawakhkha [same root as akh] sha ''''na fulanin (`it is said that a certain person travels along the path of another and that their destination is one and the same`). Or, it is stated: khuz''''ala hadha al-wakha [same root as akh] (`performs an action and takes it seriously with this intention`). So, the principle literal meaning of the word relates to people going in the same direction. A unified Ummah is a group of people who have one leader. Brothers are people who have one destination. Hence, there is a type of literal correlation between Ummah and brotherhood. Therefore, the hearts of believers - who are brothers - are brought together and their purpose and destination is one. Their concern is with Islam and its destiny. They all think about the Islamic world despite the fact that they are spread throughout the globe. The Qur''''an states: It is He who ... ` united their hearts.` (8:62- 63) This is similar to when it states: It is He who sent to the unlettered [people] an apostle ... (62:2) In other words, this action is an action that Allah performs. It is Allah who sends messengers. It is Allah who unifies the hearts. The term ''''He'''' in these verses [Allah], carries a lot of meaning. Unifying the hearts of Muslims is a divine action, not a human one. The Qur''''an raises a particular issue; just as compassion and brotherhood is found between the believers, it is found between disbelievers too. In fact, it is found between oppressors as well. But there is one difference. The brotherhood between believers is true, close, and firm because it stems from faith and the path of Allah. This brotherhood will continue between them in the Hereafter too and will carry many benefits for them. As the Qur''''an states: On that day, friends will be one another''''s enemies, except for the God wary. (43:67) This means that those who were so-called `friends` in this world will become enemies on the Day of Judgment; however, this is not the case for the pious whose corn passion between each other is firm. Nonetheless, many [amongst the disbelievers] who have a pact of brotherhood with each other will be separated on the Day of Judgment. ... Every time that a nation enters [hell], it will curse its sister [nation] ... (7:38) People in such nations will state that they had nothing to do with the other and will say to them: You misguided ` me. If you did not call me to this path I would not be in hell right now.` `Then they turned to one another, blaming each other.` (68:30) `Then on the Day of Resurrection you will disown one another and curse one another.`(29:25) The brotherhood between the believers and the pious established in the world (li-Allah) for Allah and (fi-Allah) in Allah, will remain in the Hereafter as well. The reason for this is that the compassion between the disbelievers in this world is out of mutual interest and therefore temporary; it is not real nor is it due to faith. This is the opposite of believers whose compassion for each other is real and based on faith in Allah. The Qur''''an says the following about believers and the dwellers of heaven: `We will remove whatever rancour there is in their breasts; [intimate like] brothers, [they will be reclining] on couches, facing one another.` (15:47) In fact in heaven, there is no form of enmity between the hearts of the believers. All of them are brothers to one another; all of them love one another. The same is true in the world as well. In reality, the Qur’an wants Muslims to have the same state in this world as they do in the Hereafter; or, to put it in a better way, it wants Muslims to invest in their heaven and to live like the dwellers of heaven while still on earth. This type of religious brotherhood that believers have is very valuable. Brotherhood is the biggest blessing that Allah gave to the Muslims. This brotherhood must be firm. There should not be any reason or inclination which would overshadow this brotherhood.