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

Imaam Muhammad Bin Abdul Wahhaab [rahimahullaah] said in Usoolus Sitta. “The Second Principle: Allaah has commanded Unity in the Religion and He forbade splitting in it; so Allah has clarified this with a clear clarification that is understood by the common people”.

Shaikh Zayd Bin Haadee Al-Madkhalee [rahimahullaah] commented on the above statement: I say’ this is truth stated in the Book of Allah, when Allaah [The Mighty ad Majestic] said: [ وَٱعۡتَصِمُواْ بِحَبۡلِ ٱللَّهِ جَمِيعً۬ا وَلَا تَفَرَّقُواْ‌ۚ وَٱذۡكُرُواْ نِعۡمَتَ ٱللَّهِ عَلَيۡكُمۡ إِذۡ كُنتُمۡ أَعۡدَآءً۬ فَأَلَّفَ بَيۡنَ قُلُوبِكُمۡ فَأَصۡبَحۡتُم بِنِعۡمَتِهِۦۤ إِخۡوَٲنً۬ا وَكُنتُمۡ عَلَىٰ شَفَا حُفۡرَةٍ۬ مِّنَ ٱلنَّارِ فَأَنقَذَكُم مِّنۡہَا‌ۗ – And hold fast, all of you together, to the Rope of Allaah (i.e. this Qur’aan), and be not divided among yourselves, and remember Allaah’s Favour on you, for you were enemies one to another but He joined your hearts together, so that, by His Grace, you became brethren (in Islaamic Faith), and you were on the brink of a pit of Fire, and He saved you from it]. [Surah Aal Imraan. Aayah 103]

Therefore, Allah commanded that [one] holds onto His Rope- the Firm Religion which the Book of the Lord of the Worlds and the Sunnah of the leader of the first and later Prophets- [Muhammad (Sallal-laahu-alayhi-wasallam)]- came with.  And Allaah forbade His Messenger from division in the Religion; because it is the path of the Mushrikoon and the Innovators.  As for those who possess understanding in the Religion -from the Book of their Lord and the Sunnah of their Prophet; they unite upon all affairs the Religion and they do not split- in compliance with the command given to them in the Revelation.

Unity upon the Clear Truth is the path of the Salafus Saaliheen [the pious predecessors]- those who possessed the correct understanding of Allaah’s Magnificent Book and the Sunnah of the trustworthy Prophet [sallal-laahu-alayhi-wasallam].  Splitting is the path of the people of Bidah – those who are misguided and misguiding others, because they are the ones who bring about splitting as a result of deviating from the Siraat Al-Mustaqeem.

Indeed, Allaah commanded all the Ummah to follow a single path- the Siraat Al-Mustaqeem, and warned [them] against the crooked paths. Allaah said:

وَأَنَّ هَـٰذَا صِرَٲطِى مُسۡتَقِيمً۬ا فَٱتَّبِعُوهُ‌ۖ وَلَا تَتَّبِعُواْ ٱلسُّبُلَ فَتَفَرَّقَ بِكُمۡ عَن سَبِيلِهِۦ‌ۚ

And verily, this is my Straight Path, so follow it, and follow not (other) paths, for they will separate you away from His Path. [Surah Al-An’aam. Aayah 53]

As for the people of the Qur’aan, the Sunnah and correct understanding,  they embrace this divine commandment in their hearts, tongues and with the actions of their limbs.  They do not turn away from the straight path that leads to Allaah’s  Pleasure. As for the people of Bidah, then indeed they deviate from that straight path to the other paths on the right and the left, as reported by Jaabir Bin Abdillaah [radiyallaahu-anhu] who said: We were sitting with the Prophet (sallal-laahu-alayhi-wasallam), so he drew a straight line in front of him and said, ‘this is Allaah’s path’.  He then drew lines on the right and left sides of this (straight line) and said, ‘these are the path of shaytaan’.  Then he placed his finger on the line in the middle and then recited this ayah: [  وَأَنَّ هَـٰذَا صِرَٲطِى مُسۡتَقِيمً۬ا فَٱتَّبِعُوهُ‌ۖ وَلَا تَتَّبِعُواْ ٱلسُّبُلَ فَتَفَرَّقَ بِكُمۡ عَن سَبِيلِهِۦ‌ۚ – And verily, this is my Straight Path, so follow it, and follow not (other) paths, for they will separate you away from His Path]. [Surah Al-An’aam. Aayah 153]

Therefore, whoever holds onto the middle line will be safe and happy; and whoever turns away from the middle line will follow the deviated lines, fall into destruction in this worldly life, in the Barsakh and in the hereafter. [Allaah said]: [ وَمَن لَّمۡ يَجۡعَلِ ٱللَّهُ لَهُ ۥ نُورً۬ا فَمَا لَهُ ۥ مِن نُّورٍ – And he for whom Allaah has not appointed light, for him there is no light]. [Surah An-Noor. Aayah 40]

The author [Imaam Muhammad Bin Abdul Wahhaab (rahimahullaah)] clarified that Allaah [The Mighty and Majestic] forbade splitting and differing.  And regarding the first thing related to this subject matter, Allaah [Glorified be He and free is He from all imperfections] forbade splitting in the Aqeedah, in the  Manhaj of Jihaad, in Dawah and in the Obligation of Enjoining Good and Forbidding Evil.  He clarified that splitting and differing in the Religion is a characteristic of the people of Bida’atul Mukaffirah [i.e. the bidah that nullifies one’s Islaam] and the people of Bida’atul Mufassiqah [i.e. the bidah that does not exit a person from Islaam] because all innovation in the Religion is evil, and the Prophet [sallal-laahu-alayhi-wasallam] called it ‘Misguidance’. Allaah [The Mighty and Majestic] dispraised splitting and its people with an intense dispraise in His statement:[  إِنَّ ٱلَّذِينَ فَرَّقُواْ دِينَہُمۡ وَكَانُواْ شِيَعً۬ا لَّسۡتَ مِنۡہُمۡ فِى شَىۡءٍ‌ۚ – Verily, those who divide their religion and break up into sects (all kinds of religious sects), you (O Muhammad) have no concern in them in the least. [Surah Al-An’aam. Aayah 159]

Allaah [The Might ad Majestic] said: [  وَلَا تَكُونُواْ كَٱلَّذِينَ تَفَرَّقُواْ وَٱخۡتَلَفُواْ مِنۢ بَعۡدِ مَا جَآءَهُمُ ٱلۡبَيِّنَـٰتُ‌ۚ – And be not as those who divided and differed among themselves after the clear proofs had come to them. [Surah Aal Imraan. Aayah 105]

Therefore, Allaah [The Blessed and Exalted] cautioned us- in order that we do not fall into the splitting, differing, discord an sectarianism which those before us fell into- as a mercy upon us and a clear proof, so that no one may come on the day of judgment saying, “Neither did a giver of glad tidings came to us, nor a Warner, nor did we hear a Messenger [conveying] the command of Allaah [Al-Aliyyul Kabeer], even though Allaah did command His Messenger to give glad tidings and warning.

Allaah [The Blessed and Exalted] gave an excuse [to the creation] by sending the Messengers and by way of what He assigned to [the Messengers] to convey. [Allaah said]: [ رُّسُلاً۬ مُّبَشِّرِينَ وَمُنذِرِينَ لِئَلَّا يَكُونَ لِلنَّاسِ عَلَى ٱللَّهِ حُجَّةُۢ بَعۡدَ ٱلرُّسُلِ‌ۚ – Messengers as bearers of good news as well as of warning in order that mankind should have no plea against Allaah after the Messengers]. [Surah An-Nisaa. Aayah 65]

The Prophet [sallal-laahu-alayhi-wasallam] said, “Indeed, the scholars are the inheritors of the Prophets, and the Prophets do not leave behind Dinars nor Dirhams, but they leave behind knowledge”.

Therefore, splitting in the fundamental principles and foundations of the Religion- rather in all affairs of the Religion- is blameworthy. It (splitting) is not from the characteristics of the people of Eemaan and Certainty; rather it is from the characteristics of the deviants and the innovators. As for differing in those issues of the Sharee’ah in which differing is permissible, such as differing that occurs regarding [the ruling] on some acts of worship [i.e. as to whether it is obligatory, recommended etc] or [the rulings] related some of the issues of Mutual dealing and their what is similar to them – in which differing is allowed amongst the scholars of Ijtihaad; then indeed there is no basis for splitting, hatred, turning away from one another and boycotting [in this]; rather if this occurs amongst the  scholars of Ijtihaad, then each one examines the proof, its support and basis. And when the truth is made clear even in these issues, then it becomes obligatory to embrace it and leave that which is the opposite of it.

And the important thing we should be aware of, (is that): differing in the subsidiary issues, of that which differing is allowed through Ijtihaad, [from that which is (designated) to the people of scholarly research and examination]; then there is neither a basis for cutting off one another and turning away from one another (in this affair), nor should it bring about splitting between the people.   Indeed, the Salaf used to differ in some of the [subsidiary issues of the Religion], and each had his own view; because firstly they were scholars of Ijtihaad, and secondly their differing did not enter into the blameworthy differing.  And when the truth is made clear in a matter in which differing (occurs), then it is obligatory to settle with it. And in any case, the one who is right in this differing is rewarded twice, and the one who is mistaken is rewarded once and his mistake is forgiven. [Source: An Excerpt from ‘Sullamul Wusool Ilaa Bayaan As-Sitta Al-Usool, pages 17-21. Slightly paraphrased]

Read: https://www.abukhadeejah.com/tolerated-differing-and-impermissible-differing-in-islaam/