Unity in Isalm

وَاعْتَصِمُوا بِحَبْلِ اللَّـهِ جَمِيعًا وَلَا تَفَرَّقُوا ۚ وَاذْكُرُوا نِعْمَتَ اللَّـهِ عَلَيْكُمْ إِذْ كُنتُمْ أَعْدَاءً فَأَلَّفَ بَيْنَ قُلُوبِكُمْ فَأَصْبَحْتُم بِنِعْمَتِهِ إِخْوَانًا وَكُنتُمْ عَلَىٰ شَفَا حُفْرَةٍ مِّنَ النَّارِ فَأَنقَذَكُم مِّنْهَا ۗ كَذَٰلِكَ يُبَيِّنُ اللَّـهُ لَكُمْ آيَاتِهِ لَعَلَّكُمْ تَهْتَدُونَ

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 became brothers with His blessing. And you were on the brink of a pit of Fire, whereat He saved you from it. Thus does Allah clarify His signs for you so that you may be guided. (3:103)

Allamah Tabataba’i writes in this regard:

“Holding fast to Allah” is holding fast to the verses of Allah and His Messenger (i.e., the Qur’an and the Sunnah), in which guidance has been guaranteed. Holding fast to the Messenger of Allah is, in reality, holding fast to the Qur’an; they both stem from one source. The reason for this is that Allah, in the Qur’an, orders us to obey the Prophet (s). Fundamentally, obeying Allah cannot be achieved, except through His Messenger.”

وَلَا تَكُونُوا كَالَّذِينَ تَفَرَّقُوا وَاخْتَلَفُوا مِن بَعْدِ مَا جَاءَهُمُ الْبَيِّنَاتُ ۚ وَأُولَـٰئِكَ لَهُمْ عَذَابٌ عَظِيمٌ

Do not be like those who became divided [into sects] and differed after manifest signs had come to them. For such there will be a great punishment. (3:105)

The Prophet stated that Muslim unity causes goodness and mercy while division is the factor behind destruction and punishment. He stated: “Congregating is good (a mercy) while division is torment.”

أَنْ أَقِيمُوا الدِّينَ وَلَا تَتَفَرَّقُوا فِيهِ 

وَمَا تَفَرَّقُوا إِلَّا مِن بَعْدِ مَا جَاءَهُمُ الْعِلْمُ بَغْيًا بَيْنَهُمْ

… Maintain the religion, and do not be divided in it…They did not divide [into sects] except after the knowledge had come to them, out of envy among themselves. (42:13-14)

Allamah Tabataba’i says: “Allah did not condemn division or differences in the Qur’an unless they were accompanied by carnal desires and opposition to rational guidance.”

 The Holy Prophet sawa said “Be with the community and beware of division,” “Do not cause division for those before you who caused division perished,” “Do not cause division or your hearts will become divided,” and “Whoever divided into sects before you perished.”

Again the Holy Prophet sawa  says “Believers are brothers: their blood is mutual. They are like one hand against those who are opposed to them.”

وَأَنَّ هَـٰذَا صِرَاطِي مُسْتَقِيمًا فَاتَّبِعُوهُ ۖ وَلَا تَتَّبِعُوا السُّبُلَ فَتَفَرَّقَ بِكُمْ عَن سَبِيلِهِ ۚ ذَٰلِكُمْ وَصَّاكُم بِهِ لَعَلَّكُمْ تَتَّقُونَ

‘This indeed is my straight path, so follow it, and do not follow [other] ways, for they will separate you from His way. This is what He enjoins upon you so that you may be Godwary.’ (6:153)

مِنَ الَّذِينَ فَرَّقُوا دِينَهُمْ وَكَانُوا شِيَعًا ۖ كُلُّ حِزْبٍ بِمَا لَدَيْهِمْ فَرِحُونَ

Of those who split up their religion and became sects: each faction exulting in what it possessed (30:32)

Qur’an affirms that one will not be punished for his mistakes and for what he committed out of forgetfulness, an enormous amount of attention has been paid to those who cause division intentionally (ta’ammud) and out of rebelliousness (bagha). Such actions are not to be tolerated in this world and have severe consequences in the next. 

وَإِن طَائِفَتَانِ مِنَ الْمُؤْمِنِينَ اقْتَتَلُوا فَأَصْلِحُوا بَيْنَهُمَا ۖ فَإِن بَغَتْ إِحْدَاهُمَا عَلَى الْأُخْرَىٰ فَقَاتِلُوا الَّتِي تَبْغِي حَتَّىٰ تَفِيءَ إِلَىٰ أَمْرِ اللَّـهِ ۚ

If two groups of the faithful fight one another, make peace between them. But if one party of them aggresses against the other, fight the one which aggresses until it returns to Allah’s ordinance ... (49:9)

The Prophet (s) considered the following to be one of the signs and traits of a Muslim:

“A Muslim is a person who makes other Muslims feel safe from his speech and hands.”

وَأَنَّ هَـٰذَا صِرَاطِي مُسْتَقِيمًا فَاتَّبِعُوهُ ۖ وَلَا تَتَّبِعُوا السُّبُلَ فَتَفَرَّقَ بِكُمْ عَن سَبِيلِهِ ۚ ذَٰلِكُمْ وَصَّاكُم بِهِ لَعَلَّكُمْ تَتَّقُونَ

‘This indeed is my [i.e., the Prophet’s] straight path, so follow it, and do not follow [other] ways, for they will separate you from His way. This is what He enjoins upon you so that you may be Godwary.’ (6:153)

the ‘straight path’ is the path in which there is no division.