Societies are made up of different individuals who vary in race, ethnicity and religion. Today, there is much talk about pluralistic societies and how can societal cohesion be promoted in such societies. The approach to Islam in this question is unique. In the process, it creates the strongest bond possible.
Before getting to a description of the strongest bond, it is important to note that Islam strikes at the very root of societal disunity: racism and prejudice. One can pass as many laws as one wills but as long as this disease is rooted in the heart, there can never be true social cohesion. Nothing highlights this fact more than the debates going on in Europe and the U.S. over immigration. Hatred for “foreigners,” even those who are full members and citizens of society, will always prevent true social cohesion.
Islam has wiped that disease away with one verse that indicates wherein one’s true worth lies. God has said:
“O mankind! We have created you from a male and a female, and made you into nations and tribes, that you may know one another. Verily, the most honorable of you with God is that (believer) who has piety and God-consciousness. Verily, God is All-Knowing, All-Aware.” (Quran 49:13)
Hence, race and ethnicity should have no effect whatsoever with respect to societal cohesion in the eyes of a Muslim. There is, though, a difference that Islam does take into consideration: the difference of faith and religion. Hence, this discussion of societal cohesion will be focused on societal cohesion in the context of a pluralistic society with respect to religion.
The Bond of Faith
If one were to ask many today as to what the strongest bond there could possibly be among people, most of them would probably answer something like blood relationship, ethnic origin, nationality and so forth. Actually, the Quran shows that these types of bonds are not that strong if the foundation behind them is weak. In the Quran, God gives the examples of Cain and Abel, who were two brothers yet one killed the other, as well as the example of the brethren of Joseph, who cast Joseph into a well. Those were all blood relatives; however, they put this world above their relationship with others. Such is occurring today throughout the world. The ties between the people are subservient to their desires, goals and wants of this world. Many individuals are quickly and easily willing to sell out their own kith and kin to get ahead in this world or to get something they want in this world.
All of this demonstrates one thing: When the ties between people are based on worldly considerations, even if they are originally blood ties, then those ties are given up when the worldly considerations so demand them to be given up. Hence, those are not the strongest ties that can be built among people. The strongest ties that can be achieved between people are the ties of Islam and true faith. These are the bonds forged between people that are solely the result of their belief in God and their love for God. This was clearly pointed out by God in the Quran when God stated:
“And He has united their (believers’) hearts. If you had spent all that is in the earth, you could not have united their hearts, but God has united them. Certainly, He is All-Mighty, All-Wise.” (Quran 8:63)
God also says:
“And hold fast, all of you together, to the Rope of God, and be not divided among yourselves, and remember God’s favor on you, for you were enemies and He joined your hearts together, so that by His grace, you became brethren and you were on a brink of a Pit of Fire, and He saved you from it. Thus God makes clear His signs to you, that you may be guided.” (Quran 3:103)
The Quran and the Sunnah show that the bond of faith is the strongest of all bonds. It represents humans from all over the world coming together for one purpose only: to establish the worship God alone. To achieve that goal, Muslims work together and help one another in compassion mercy and love.
There are actually numerous texts of the Quran and hadith that demonstrate beyond any doubt that Muslims are to form one universal, international brotherhood and sisterhood.  For the sake of brevity, only a few examples of those texts will be presented here:
“The believers, men and women, are auliyaa (helpers, supporters, friends, protectors) of one another, they enjoining what is good and eradicate what is evil. They offer the prayers and pay the zakat and obey God and His Messenger. Surely, God will have His Mercy on them. Surely, God is All-Mighty, All-Wise.” (Quran 9:71)
Another verse reads:
“The believers are nothing else but brothers…” (Quran 49:10)
God also says:
“Muhammad is the Messenger of God, and those who are with him are severe against disbelievers and merciful among themselves…” (Quran 48:29)
The Prophet, may the mercy and blessings of God be upon him, said:
“The believer with respect to another believer is like a building, one portion strengthening the other.” (Saheeh al-Bukhari and Saheeh Muslim)
Another hadith states:
“The parable of the believers with respect to their love, mercy and compassion for one another is like that of the body: if one of its limbs is hurting, the remainder of the body is afflicted by sleeplessness and fever.” (Saheeh Muslim)
But this great brotherhood of Islam is not something simply theoretical. It is, in fact, well defined and supported by practical guidance.  It has certain basic components to it and specific rights and obligations that are spelled out in the Quran and Sunnah. These rights and obligations are due to every Muslim, of every time and place.
One of the necessary aspects of this brotherhood is love. That is, it is an obligation upon all Muslims to love their brother Muslims. In fact, they should love them in a manner similar to the way they care for themselves. As the Prophet, may the mercy and blessings of God be upon him, said:
“None of you truly believes until he loves for his brother what he loves for himself.” (Saheeh Al-Bukhari, Saheeh Muslim)
A second necessary aspect of this brotherhood is mutual support, aid and assistance. When his brother is being oppressed or wronged, he comes to his aid and assistance with his wealth and soul, if possible. This is described, for example, in the following verses:
“And what is wrong with you that you fight not in the Cause of God, and for those weak, ill-treated and oppressed among men, women and children, whose cry is, ‘Our Lord! Rescue us from this town whose people are oppressors, and raise for us from You one who will protect, and raise for us from You one who will help.’” (Quran 4:75)
A third essential aspect of this Islamic brotherhood is mercy and tenderness between the believers. This goes beyond a simple love for one another but it means that each brother feels in his heart for what his brother is going through. The Prophet described the Muslims in the following fashion:
“The similitude of believers in regard to mutual love, affection, fellow-feeling is that of a body; when any limb of it aches, the whole body aches due to fever and sleeplessness.” (Saheeh Muslim)
A final necessary component of our brotherhood is common acts of courtesy. True brotherhood has to be put into practice; it cannot simply be a statement of the tongue. One amazing and beautiful aspect of Islam is that it does not leave matters at a hypothetical level with each individual attempting to figure out how goals can possibly be achieved. Thus, for example, the Prophet has detailed specific acts that one has the right to expect from one’s brother and which one should also perform towards one’s brother. Thus, among those common obligatory acts of courtesy are the six mentioned by the Prophet:
“Six are the rights of a Muslim over another Muslim.... When you meet him, offer him greetings; when he invites you to a feast, accept it; when he seeks your sincere counsel, give it to him; when he sneezes and says, ‘al-hamdulillah,’ say, ‘May God show mercy to you’; when he falls ill, visit him; and when he dies, follow his funeral bier.” (Saheeh Muslim)
Beyond these six well-known practices, Islamic Law guides Muslims to many other practices that help gender love and closeness between the believers, which is an obvious goal of the Law itself. Thus, for example, if a Muslim loves another Muslim for the sake of God, he should inform the other individual of that feeling. The Prophet explained the reason for doing so when he said:
“If one of you loves his brother for the sake of God, he should inform of that as this will make the bond longer lasting and the love more confirmed.” 
The Prophet also said:
“By the One in whose hand is my soul, you will not enter Paradise until you believe. And you do not believe until you love one another. Certainly, let me inform you of that which will establish such for you: spreading peace among yourselves.” (Saheeh Muslim)
This hadith could mean the spreading of the greetings of peace or doing actual deeds that bring about peace and togetherness.
The Prophet also noted the importance of giving gifts to one another. He said:
“Exchange gifts and you will love one another.” (As-Suyooti)
The Prophet also encouraged Muslims to visit one another. He stated:
“Visit one another occasionally and love [between you] will increase.” (al-Tabaraani)
In addition to all of these positive acts, when one avoids the forbidden acts, the results will also be positive for interpersonal relationships. In other words, when one avoids backbiting, slandering, lying, cheating, spying and so forth, nothing but good will result from the avoidance of these evil practices that Islam has clearly forbidden.
Thus, one can conclude that social cohesion among Muslims is definitely one of the most sought after goals in Islam. In addition, practical steps are laid down to ensure that this goal will be met.
A Muslim vis-à-vis Non-Muslims
Obviously, society will not consist of Muslims alone. Furthermore, Muslims and non-Muslims are following very different paths. A Muslim’s life revolves entirely around the proper belief in God. A Muslim’s attitude toward others is likewise determined by the other’s attitude toward God. A Muslim could not possibly feel complete affinity and love toward someone who has turned his back on God, refuses to submit to God or ridicule belief in God. It is simply not natural for there to be complete love between two such people.  However, even given this possible negative feeling in the heart, a Muslim must deal with non-Muslims on the basis of just principles. This applies to all non-Muslims—many non-Muslims are not antagonistic at all toward Muslims while others exhibit clear and unequivocal scorn and hatred toward Muslims. 
One of the basic principles of behavior toward non-belligerent, non-Muslims is found in the following verse of the Quran:
“God forbids you not to deal justly and kindly with those who fought not against you on account of religion and drove you not out from your homes. Verily, God loves those who deal with equity” (Quran 60:8)
An important obligation toward disbelievers is proper and just treatment. This is described by a well-known Muslim scholar, Shaikh ibn Baaz, who said:
“[the Muslim] may not wrong the other person with respect to his life, wealth or honor, if the non-Muslim is a citizen of the Islamic state or has attained other protection. He must fulfill the other’s rights. He may not wrong him with respect to his wealth by stealing from him, deceiving him or cheating him. He cannot harm him in his body by beating or killing him. His protection from the state guarantees his safety from such things.” 
A Muslim can interact with non-Muslims, buying, selling or renting from them, for example.  Even on a social level, there can be interaction, such as coming together for meals and the like. However, such interactions are, by nature, going to be limited, due to differences in societal practices and customs. Perhaps one could say that the Muslim’s ultimate goal in his relations with non-Muslims is to bring them to Islam, thereby opening the door for there to be a complete relationship of love and brotherhood between them. Even if the non-Muslim is antagonistic and impolite, the Muslim knows that he should repel his evil with goodness. God says:
“The good deed and the evil deed cannot be equal. Repel [the evil] with [a deed] that is better. [If you do that] then verily he, between whom and you there was enmity, (will become) as though he was a close friend” (Quran 41:34)
In sum, as ibn Baaz wrote:
“It is obligatory upon Muslims to deal with disbelievers in an Islamic fashion with proper behavior, as long as they are not fighting the Muslims. One must fulfill one’s trusts to them, must not deceive them, must not betray them or lie to them. If there is a discussion or debate between them, one must argue with them in the best manner and be just with them in the dispute. This is in obedience to God’s command:
“And argue not with the People of the Scriptures (Jews and Christians) unless it be in a way that is better, except with such of them as do wrong” (Quran 29:46)
It is sanctioned for the Muslim to invite them to the good, to advise them and to be patient with them at the same time being neighborly and polite with them. This is so because God has stated:
“Invite to the way of your Lord with wisdom (of the Quran) and fair preaching, and argue with them in a way that is better” (Quran 16:125)
God has also said:
“…Speak good to people…” (Quran 2:83) 
A Muslim vis-à-vis Society as a Whole
When a Muslim accepts to live in a certain society, he is, in essence, making a pact that with that country that he will abide by the laws of that state. He does not have the right to violate the laws of that state simply because he is a Muslim and the state is not an Islamic state. Thus, all of the principles of proper behavior that have been described in this chapter apply to a Muslim living wherever he may be living. In most countries today, many things may be legal that are forbidden to a Muslim. These legal things a Muslim simply avoids. He should also demand his legal rights to ensure that he is not forced to do anything forbidden in Islam. Overall though, he should be from among the law-abiding citizens.
In addition to that, a Muslim should be a plus for any society he is living in. He should be a model citizen in many ways. As described earlier, he should be a good neighbor. He has the obligation to encourage what is good and prevent evil wherever he may be living. In addition, he must avoid and oppose what most societies see as the greatest crimes, such as murder, robbery, extortion and so forth. Furthermore, he must steer clear of alcohol or drug use, thus not burdening society as a whole with his personal weaknesses and addictions. Finally, he must be just and fair in all of his dealings with the other members of society.
Islam recognizes the fact that it is natural for an individual to love his country and to have an affinity for that land in which he grew up. When the Muslims were forced to migrate from Makkah, which was under the control of the polytheists, many of them expressed their love for Makkah. Hence, it is natural for Muslims to develop a love for whatever land they happen to be in, even if the country is not an Islamic state. It is also natural for Muslims to desire what is best for their homeland. But, again, unfortunately, their idea as to what is best may not be shared or appreciated by others. For example, the Muslims may wish to see an end to gambling, prostitution and pornography. The Muslims believe that this is what is best for all the people concerned, Muslims as well as non-Muslims. However, many non-Muslims will not share this feeling. Therein lies the crux of the problem. Theoretically speaking, though, in contemporary “free” societies, this should not be a problem. Muslims should be able to hold on to their values and customs—without bringing harm to others—while the others follow the dominant culture in non-Muslim lands. If the “free” countries are not willing to give the Muslims that much, it means that they are not willing to live up to their own ideals. It is not that Muslims are trying to cause them harm, they are simply trying to be good citizens while living a different lifestyle than the dominant culture.
Even in pluralistic societies, Islamic teachings contribute to societal cohesion. First, the major stumbling block to such cohesion, racism and prejudice, is removed. Second, a strong love and bond is created between those of the Islamic faith. Third, clear and decisive instructions of just and proper behavior are given for treatment with those outside of the bond of faith. Fourth, the Muslim understands his responsibility towards those around him and therefore contributes to the good of all, further enhancing good feelings and cohesion within society.
 It is important to realize that this brotherhood is founded upon a common faith. In fact, blood relationships come to an end because of differences in religion. God says about Noah and his son, “[Noah said,] ‘O my Lord, verily my son is of my family! And certainly your promise is true, and You are the Most Just of the judges.’ He [God] said, ‘O Noah! Surely he is not of your family, his work is unrighteous’” (Quran 11:45-46). Hence, non-Muslims fall outside of the fold of this brotherhood. They are more than welcome to join this brotherhood by embracing Islam, as this brotherhood is not based on race, ethnicity or nationality. Otherwise, by their choice of religion and belief they have opted to remain outside of this brotherhood. As shall be discussed later, the Muslim still has obligations toward such non-Muslims.
It is a great blessing that in Islam one finds detailed teachings that result in their desired goals while, at the same time, being extremely practical and consistent with human nature. The lack of such teachings is one of the greatest dilemmas faced by Christianity. With respect to societal cohesion, the greatest teachings found in the New Testament are what are known as “the hard sayings” of Jesus. They are as follows: “Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth: But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also. And if any man will sue thee at the law, and take away thy coat, let him have thy cloak also. And whosoever shall compel thee to go a mile, go with him twain. Give to him that asketh thee, and from him that would borrow of thee turn not thou away. Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy. But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you; That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust. For if ye love them which love you, what reward have ye? do not even the publicans the same? And if ye salute your brethren only, what do ye more than others? do not even the publicans so? Be ye therefore perfect, even as your Father which is in heaven is perfect” (Matthew 5:38-48). (Note that Muslims are well aware of the fact that Jesus’ words were not preserved properly and therefore one cannot truly argue that these were his words.) Christian scholars themselves are perplexed. How are such obviously impossible or impractical teachings to be applied? Just one example of a discussion of these words will suffice to show how perplexing they are: “[For interpreting these words, t]he model proposed by Joachim Jeremias is simple, representative, and of continuing influence. According to this model, the Sermon usually is seen in one of three ways: (1) as a perfectionist code, fully in line with the legalism of rabbinic Judaism; (2) as an impossible ideal, meant to drive the believer first to desperation, and then to trust in God's mercy; or (3) as an "interim ethic" meant for what was expected to be a brief period of waiting in the end time, and which is now obsolete. Jeremias adds his own fourth thesis: The Sermon is an indicative depiction of incipient life in the kingdom of God, which presupposes as its condition of possibility the experience of conversion. More complex or comprehensive schematizations have been offered, but most major interpreters can be understood in relation to the options posed by Jeremias.” Lisa Sowle Cahill, Love Your Enemies: Discipleship, Pacifism, and Just War Theory (Minneapolis, MN: Fortress Press, 1994), p. 27..
 Recorded by ibn Abi Dunya in Kitaab al-Ikhwaan.
 This fact is true for secularists as well. Many of those on the left side of the political scale feel true scorn and enmity toward those on the right, and vice-versa.
 There are times in which Islamic states may go to war with non-Muslim states. Such conditions of belligerency are not uncommon in the history of humankind and do not necessarily imply the impossibility of some cooperation in the future. In fact, European states constantly fought each other, sometimes for a hundred years’ time, and yet today they all belong to the European Union. A state of belligerency will affect the relationship between such Muslims and non-Muslims. However, that is not the normal case in the world today. Thus, a discussion of those cases is beyond the scope of this work.
 Ali Abu Lauz, compiler, Answers to Common Questions from New Muslims (Ann Arbor, MI: IANA, 1995), p. 30.
 Issues concerning non-Muslim relatives or non-Muslim neighbors have already been touched upon..
 Ali Abu Lauz, Answers, p. 42.