Solidarity among Muslims is a Shari`ah-based obligation, enjoined by Allah Almighty in the Qur’an and in the Sunnah of the Prophet (peace and blessings be upon him). It is also urged by the sense of brotherhood among Muslims, and the general welfare of the Muslim Ummah also requires this. There are many forms of solidarity, according to different circumstances, traditions, ages and places.
The late Sheikh Ibn Baz, the former Mufti of Saudi Arabia, states the following: There are many Qur’anic verses that indicate the obligation of solidarity among Muslims. Among them is that in which Allah (Exalted and Blessed be He) says: (By the declining day, Lo! man is in a state of loss, save those who believe and do good works, and exhort one another to truth and exhort one another to endurance.) (Al-`Asr 103: 1-3)

In this short Qur’anic surah, Allah Almighty declares that there is no way for success, well-being, good reward and deliverance from all forms of loss except in true faith in Allah, good deeds, and mutual advice to truth and endurance in defending it. The reality of things from the time Allah sent Prophet Muhammad (peace and blessings be upon him) up till now is the best witness to the message included in this noble surah and a firm proof of it.
When, after the Prophet’s death, Muslims started to violate the great principles of Islam, they suffered from differences, disunity and enmity, as we all know. In fact, there is no therapy for such suffering except for Muslims to turn to the basics of Islam, stick tightly to it, work in accordance to its tenets, and make it the guide and reference in their conflicts. Allah Almighty says: (But nay, by thy lord, they will not believe (in truth) until they make thee judge of what is in dispute between them and find within themselves no dislike of that which thou decidest, and submit with full submission.) (An-Nisaa’ 4: 65)
Allah also says: (O ye who believe! Obey Allah, and obey the Messenger and those of you who are in authority; and if ye have a dispute concerning any matter, refer it to Allah and the Messenger if ye are (in truth) believers in Allah and the Last Day. That is better and more seemly in the end.) (An-Nisaa’ 4: 59)
There are also many Prophetic hadiths concerning the issue of solidarity in Islam, which means cooperation in the cause of piety and goodness. The Prophet (peace and blessings be upon him) said: “Indeed, the religion is [based on sincere] advice.” The Companions asked: “To whom, Messenger of Allah?” He said: “For Allah, His Messenger, the rulers from among the Muslims, as well as their common folk.” (Reported by Muslim)
the Prophet (peace and blessings be upon him) also said: “The relation of a believer to his brother in faith is as strong as a building whose parts support one another.” (While saying so, the Prophet held his fingers tight [as a sign of solidarity])
Moreover, the Prophet (peace and blessings be upon him) is reported to have said: “The solidarity of Muslims in their mutual love, mercy and sympathy, is that of a body; if an organ aches, the whole body sympathizes with it with sleeplessness and fever.” (Reported by Al-Bukhari and Muslim)
these hadiths and others with the same content explicitly indicate the obligation of mutual solidarity, mercy, sympathy and cooperation among Muslims in the cause of goodness. The Prophet (peace and blessings be upon him) compared the Muslims once to a building and once to the body. Such images indicate that mutual solidarity, mercy and cooperation will gather the Muslims on the same word and the same principles, and thus they will unite in their stance against the enemies of Islam.
the imam and guide of the Muslim Ummah in their honorable call to goodness is the great leader, Prophet Muhammad (peace and blessings be upon him). He is the first who called the Muslim Ummah to worship Allah Alone and hold fast to the way of Allah. He united the Ummah under the banner of Truth to stand firm in the face of their enemy and defend their fair rights in the face of tyranny, as indicated in Allah’s Words: (Call unto the way of thy Lord with wisdom and fair exhortation, and reason with them in the better way.) (An-Nahl 16: 125) Allah also says: (Say: This is my Way: I call on Allah with sure knowledge, I and whosoever followeth me.) (Yusuf 12: 108)
The Prophet’s Companions (may Allah be pleased with them all) and their righteous successors followed in the footsteps of the Prophet (peace and blessings be upon him) and they were overwhelmingly successful, and Allah Almighty fulfilled His promise to them; He honored them and gave them victory over their enemy.
It is undeniable that Allah bestowed success on them by virtue of their true faith, hard striving in His cause, good deeds, patience and endurance, sincerity in word and deed, and their solidarity and cooperation in this course. Allah does not judge people according to their families or wealth, as He Almighty says: (And it is not your wealth nor your children that will bring you near unto Us, but he who believeth and doeth good (he draweth near). As for such, theirs will be twofold reward for what they did, and they will dwell secure in lofty halls.) (Saba’ 34: 37)
the Prophet (peace and blessings be upon him) also said: “Verily, Allah does not consider your shape or wealth; rather He considers your hearts and deeds.” (Reported by Muslim)
So, whoever takes the same track of the righteous and follows their footsteps will attain the same reward Allah gave them, and He will give him victory as He did with the righteous. Allah Almighty says: (Lo! We verily do help Our messengers, and those who believe, in the life of the world and on the day when the witnesses arise, the day when their excuse availeth not the evil doers, and theirs is the curse, and theirs the ill abode.) (Ghafir 40: 51-52)
Allah also says: (And verily Our word went forth of old unto Our bondmen sent (to warn); that they verily would be helped, and that Our host, they verily would be the victors.) (As-Saffat 37: 171-173)
Allah Almighty also says: (To help believers is incumbent upon Us.) (Ar-Rum 30: 47)
Allah Almighty takes it upon Himself to support His obedient servants and gather them under the banner of Truth. It is Allah Who furnishes people with sound understanding in their religion, bestows success upon rulers, and guides them to the right path. Allah strengthens the union of solidarity among Muslims and blesses them for their mutual advice and cooperation in the cause of goodness. Allah also protects His righteous servants against disunity, controversy, temptation and wicked schemes. Allah is the Owner of the universe, and He regulates it.
It is incumbent on Muslims to unite under the banner of Islam rather than be disunited under different banners. Some countries are united for joint economic interest, others for strategic purposes, and still some others succumb under the grasp of disguised occupation. There are regional organizations and race- or creed-based organizations. What is most amazing is that no religion calls for solidarity and cooperation as Islam does, even though Muslims witness the least degree of unity and solidarity in relation to other nations.
Many Levels of Solidarity
a certain form of solidarity was achieved under the Islamic Caliphate. Hence, it is the duty of Muslim states to unite under the banner of Islam and to cooperate with other non-Muslim countries on humanitarian bases that do not contradict the tenets of Islam.
then there must be unity among peoples of different Islamic states through different regional and international organizations that aim to activate the role of people in achieving solidarity among the whole Ummah. Such kind of organizations must be developed to consider the anti-Islam campaigns that are plotted all the time to uproot Islam. Their role must extend to propagating Islam as the resort for lost mankind, who is sinking in a sea of vulgarness and degeneration.
Lastly, there should be internal cooperation between the systems of each state—media, economic, political, social, and religious, —for Islam is a complete way of life in all aspects. The main end for Muslims should be to show Islam in its pure essence to the world, for people to understand it in the right way and follow its guidance. Then let the stubborn disbelieve.
Moreover, unity in the face of the enemy is a form of solidarity. Hence, there should be a united body of Muslim forces ready to defend Islam and protect Muslim countries from invasion. In the same way, members of the same field in Muslim countries can achieve solidarity by working together for the benefit of their home, for the Ummah, and for the whole of mankind.