وَاعْتَصِمُواْ بِحَبْلِ اللّهِ جَمِيعًا وَلَا تَفَرَّقُواْ
And hold fast, all of you together, to the Rope of Allah, and be not divided among yourselves.
It was said that,
بِحَبْلِ اللّهِ
(to the Rope of Allah),
refers to Allah's covenant, just as Allah said in the following Ayah,
ضُرِبَتْ عَلَيْهِمُ الذِّلَّةُ أَيْنَ مَا ثُقِفُواْ إِلاَّ بِحَبْلٍ مِّنْ اللّهِ وَحَبْلٍ مِّنَ النَّاسِ
(Indignity is put over them wherever they may be, except when under a covenant (of protection) from Allah, and from men); (3;112) in reference to pledges and peace treaties.
Allah's statement
وَلَا تَفَرَّقُواْ
(and be not divided among yourselves),
orders sticking to the community of the believers and forbids division.
There are several Hadiths that require adhering to the Jama`ah (congregation of believers) and prohibit division.
Muslim recorded that Abu Hurayrah said that the Messenger of Allah said,
إِنَّ اللهَ يَرْضَى لَكُمْ ثَلَثًا وَيَسْخَطُ لَكُمْ ثَلَثًا
يَرْضَى لَكُمْ
أَنْ تَعْبُدُوهُ وَلَا تُشْرِكُوا بِهِ شَيْيًا
وَأَنْ تَعْتَصِمُوا بِحَبْلِ اللهِ جَمِيعًا وَلَاأ تَفَرَّقُوا
وَأَنْ تَنَاصَحُوا مَنْ وَلاَّهُ اللهُ أَمْرَكُمْ
وَيَسْخَطُ لَكُمْ ثَلَثًا
قِيلَ وَقَالَ
وَكَثْرَةَ السُّوَالِ
وَإِضَاعَةَ الْمَال
It pleases Allah for you to acquire three qualities and displeases Him that you acquire three characteristics.
It pleases Him that;
you worship Him Alone and not associate anything or anyone with Him in worship,
that you hold on to the Rope of Allah altogether and do not divide, and
that you advise whoever Allah appoints as your Leader.
The three that displease Him are that;
you say, `It was said,' and, `So-and-so said,'
asking many unnecessary questions and
wasting money.
Allah said,
وَاذْكُرُواْ نِعْمَةَ اللّهِ عَلَيْكُمْ إِذْ كُنتُمْ أَعْدَاء فَأَلَّفَ بَيْنَ قُلُوبِكُمْ فَأَصْبَحْتُم بِنِعْمَتِهِ إِخْوَانًا
and remember Allah's favor on you, for you were enemies one to another but He joined your hearts together, so that, by His grace, you became brethren.
This was revealed about the Aws and Khazraj. During the time of Jahiliyyah, the Aws and Khazraj were at war and had great hatred, enmity and ill feelings towards each other, causing long conflicts and battles to occur between them. When Allah brought Islam, those among them who embraced it became brothers who loved each other by Allah's grace, having good ties for Allah's sake and helping each other in righteousness and piety.
Allah said,
هُوَ الَّذِيَ أَيَّدَكَ بِنَصْرِهِ وَبِالْمُوْمِنِينَ
وَأَلَّفَ بَيْنَ قُلُوبِهِمْ لَوْ أَنفَقْتَ مَا فِي الَارْضِ جَمِيعاً مَّا أَلَّفَتْ بَيْنَ قُلُوبِهِمْ وَلَـكِنَّ اللّهَ أَلَّفَ بَيْنَهُمْ إِنَّهُ عَزِيزٌ حَكِيمٌ
He it is Who has supported you with His Help and with the believers. And He has united their hearts. If you had spent all that is in the earth, you could not have united their hearts, but Allah has united them. Certainly He is All-Mighty, All-Wise.(8;62-63)
وَكُنتُمْ عَلَىَ شَفَا حُفْرَةٍ مِّنَ النَّارِ فَأَنقَذَكُم مِّنْهَا كَذَلِكَ يُبَيِّنُ اللّهُ لَكُمْ ايَاتِهِ لَعَلَّكُمْ تَهْتَدُونَ
and you were on the brink of a pit of Fire, and He saved you from it. Thus Allah makes His Ayat clear to you, that you may be guided.
Before Islam, their disbelief had them standing at the edge of a pit of the Fire, but Allah saved them from it and delivered them to faith. The Messenger of Allah reminded the Ansar (from both Aws and Khazraj) of this bounty when he was dividing the war booty of Hunayn. During that time, some Ansar did not like the way the booty was divided, since they did not get what the others did, although that was what Allah directed His Prophet to do.
The Messenger of Allah gave them a speech, in which he said,
يَا مَعْشَرَ الاْاَنْصَارِ أَلَمْ أَجِدْكُمْ ضُلَّلاًا فَهَدَاكُمُ اللهُ بِي
وَكُنْتُمْ مُتَفَرِّقِينَ فَأَلَّفَكُمُ اللهُ بِي
وَعَالَةً فَأَغْنَاكُمُ اللهُ بِي
O Ansar! Did I not find you misguided and Allah directed you to guidance because of me!
Were you not divided beforehand and Allah united you around me!
Were you not poor and Allah enriched you because of me!
Whenever the Prophet asked them a question, they would answer, "Indeed, Allah and His Messenger have granted us bounty.