In The Name of Allah, The Most Merciful, The Bestower of Mercy.

Shaikh Islam Ibn Taymiyyah, may Allah have mercy upon him, said: 

The one who abandons the truth or some of it will be tried with falsehood. This is the case with ahlul bidah. You will not find anyone who has abandoned some of the Sunnah that should be affirmed and acted upon, except that he falls into bidah. You will not find a person of Bidah except that he has abandoned something from the Sunnah, as reported in the narration “A people do not bring about a Bidah, except after abandoning something similar to it of the Sunnah”.

Allah, The Most High, said:

 فَنَسُواْ حَظًّ۬ا مِّمَّا ذُڪِّرُواْ بِهِۦ فَأَغۡرَيۡنَا بَيۡنَهُمُ ٱلۡعَدَاوَةَ وَٱلۡبَغۡضَآءَ

But they have abandoned a good part of the Message that was sent to them.  So We planted amongst them enmity and hatred. [Al-Maa’idah. 14]

After they abandoned a part of the message that was sent to them, they then held onto other than it, thus enmity and hatred occurred between them.

Allah said:

وَمَن يَعۡشُ عَن ذِكۡرِ ٱلرَّحۡمَـٰنِ نُقَيِّضۡ لَهُ ۥ شَيۡطَـٰنً۬ا فَهُوَ لَهُ ۥ قَرِينٌ۬

And whosoever turns away (blinds himself) from the remembrance of the Most Beneficent (Allah) (i.e. this Qur’aan and worship of Allah), We appoint for him Shaitaan (Satan  devil) to be a Qareen (an intimate companion) to him. [Az-Zukhruf. 36]

Allah said:

فَإِمَّا يَأۡتِيَنَّڪُم مِّنِّى هُدً۬ى فَمَنِ ٱتَّبَعَ هُدَاىَ فَلَا يَضِلُّ وَلَا يَشۡقَىٰ

وَمَنۡ أَعۡرَضَ عَن ذِڪۡرِى فَإِنَّ لَهُ ۥ مَعِيشَةً۬ ضَنكً۬ا وَنَحۡشُرُهُ ۥ يَوۡمَ ٱلۡقِيَـٰمَةِ أَعۡمَىٰ

Then if there comes to you guidance from Me, then whoever follows My Guidance shall neither go astray, nor fall into distress and misery.  But whosoever turns away from My Reminder (i.e. neither believes in this Qur’aan nor acts on its orders, etc.) verily, for him is a life of hardship, and We shall raise him up blind on the Day of Resurrection. [Ta Ha 123-124]

Allah said:

ٱتَّبِعُواْ مَآ أُنزِلَ إِلَيۡكُم مِّن رَّبِّكُمۡ وَلَا تَتَّبِعُواْ مِن دُونِهِۦۤ أَوۡلِيَآءَ‌ۗ قَلِيلاً۬ مَّا تَذَكَّرُونَ

Follow what has been sent down unto you from your Lord (the Qur’aan and Prophet Muhammad’s Sunnah), and follow not any Auliyaa’ (protectors and helpers, etc. who order you to associate partners in worship with Allah), besides Him (Allah). Little do you remember! [Al-A’raaf. 3]

They have been commanded to follow what has been sent down, and prohibited from that which is in opposition to it, which is to follow protectors and helpers besides Him (Allah). Therefore, whoever does not follow one of them will follow the other. This is why Allah said:

وَمَن يُشَاقِقِ ٱلرَّسُولَ مِنۢ بَعۡدِ مَا تَبَيَّنَ لَهُ ٱلۡهُدَىٰ وَيَتَّبِعۡ غَيۡرَ سَبِيلِ ٱلۡمُؤۡمِنِينَ نُوَلِّهِۦ مَا تَوَلَّىٰ وَنُصۡلِهِۦ جَهَنَّمَ‌ۖ وَسَآءَتۡ مَصِيرًا

And whoever contradicts and opposes the Messenger (Muhammad) after the right path has been shown clearly to him, and follows other than the believers’ way [i.e. the Sahabah]; we shall keep him in the path he has chosen, and burn him in Hell – what an evil destination. [An-Nisaa. 115]

The scholars state:

“The one who does not follow their path [i.e. the path of the Sahabah] will follow other than their path”.

They utilise this as proof (to show) that it is obligatory to follow their path.  And it is not for anyone to leave that which they are agreed upon. [end of quote] [1]

Shaikh Al-Islam Ibn Taymiyyah, may Allah have mercy upon him, said:

“Bidah is associated with splitting just as the Sunnah is associated with the Jama’ah, thus, it is said Ahlus Sunnah Wal-Jama’ah just as it is said Ahlul Furqah Wal Bidah”. [2]

[1] An Excerpt from “Adwaa Min Fatawa 2/864’. By Mufti, Al-Allamah Salih Al-Fawzan, may Allah preserve him.

[2] al-Istiqamah 1/41