The Sunnah

And hold fast, all of you together, to the Rope of Allah

قال الله تعالى: ﴿وَلْتَكُن مِّنْكُمْ أُمَّةٌ يَدْعُونَ إِلَى الْخَيْرِ وَيَأْمُرُونَ بِالْمَعْرُوفِ وَيَنْهَوْنَ عَنِ الْمُنْكَرِ وَأُوْلَـئِكَ هُمُ الْمُفْلِحُونَ - وَلاَ تَكُونُواْ كَالَّذِينَ تَفَرَّقُواْ وَاخْتَلَفُواْ مِن بَعْدِ مَا جَآءَهُمُ الْبَيِّنَـتُ وَأُوْلَـئِكَ لَهُمْ عَذَابٌ عَظِيمٌ - يَوْمَ تَبْيَضُّ وُجُوهٌ وَتَسْوَدُّ وُجُوهٌ فَأَمَّا الَّذِينَ اسْوَدَّتْ وُجُوهُهُمْ أَكْفَرْتُمْ بَعْدَ إِيمَـنِكُمْ فَذُوقُواْ الْعَذَابَ بِمَا كُنْتُمْ تَكْفُرُونَ - وَأَمَّا الَّذِينَ ابْيَضَّتْ وُجُوهُهُمْ فَفِى رَحْمَةِ اللَّهِ هُمْ فِيهَا خَـلِدُونَ - تِلْكَ ءَايَـتُ اللَّهِ نَتْلُوهَا عَلَيْكَ بِالْحَقِّ وَمَا اللَّهُ يُرِيدُ ظُلْماً لِّلْعَـلَمِينَ ﴾ سورة ال عمران 

Allah the Exalted says,

(104.Let there arise out of you a group of people inviting to all that is good , enjoining Al-Ma`ruf and forbidding Al-Munkar. And it is they who are the successful.) (105. And be not as those who divided and differed among themselves after the clear proofs had come to them. It is they for whom there is an awful torment.) (106. On the Day (i.e. the Day of Resurrection) when some faces will become white and some faces will become black; as for those whose faces will become black (to them will be said): "Did you reject faith after accepting it Then taste the torment (in Hell) for rejecting faith.'') (107. And for those whose faces will become white, they will be in Allah's mercy (Paradise), therein they shall dwell forever.) (108. These are the Ayat of Allah. We recite them to you in truth, and Allah wills no injustice to mankind.)

Allah forbids this nation from becoming misguided as the past nations did by disputing and dividing.

Imam Ahmed narrated that Abu `Amir al-Hawdhani said:

"We performed Hajj with Mu`awiyah b. Abi Sufiyan, when we reached Makkah, he stood among us after performing Thuhr salah and said: Beware! The Apostle of Allah (ﷺ) stood among us and said: Beware! The people of the two Books before were split up into seventy two sects, and this ummah will be split into seventy three -meaning desires-: seventy two of them will go to Hell and one of them will go to Paradise, and it is the majority group, and there will appear among my ummah people who will be dominated by desires like rabies which penetrates its patient, there remains no vein and no joint but it penetrates it.”

And from another narration, the prophet was asked about the saved group/sect, he, sala Allahu alehe wasalm, said, "those who remain upon what am I upon along with my companions"

Allah the truthful, the exalted says,

وَمَن يُشَاقِقِ الرَّسُولَ مِن بَعْدِ مَا تَبَيَّنَ لَهُ الْهُدَى وَيَتَّبِعْ غَيْرَ سَبِيلِ الْمُؤْمِنِينَ نُوَلِّهِ مَا تَوَلَّى وَنُصْلِهِ جَهَنَّمَ وَسَآءَتْ مَصِيراً

"And whoever opposes the Messenger after guidance has become clear to him and follows other than the way of the believers - We will give him what he has taken and drive him into Hell, and evil it is as a destination."