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

Imam Al-Barbahaaree, may Allah have mercy upon him, said:

Know that leaving the correct path occurs in two ways. Firstly, a man strays from the correct path intending nothing but good, so his error is not to be followed since it leads to destruction. Secondly, a man who deliberately opposes the truth and acts contrary to the Pious ones who came before him, is astray, leading others astray, a rebellious devil within the Ummah. It is a duty upon those who know of him to warn the people against him and to explain his condition to them so that no one falls into his innovation and is destroyed.

Al-Allamah Salih Al-Fawzan, may Allah preserve him], commented:

The first man leaves the (correct path) without the intending (to do so), rather he intended good, but followed other than the path of good. Striving (alone) is not sufficient, and even if the person has a righteous intention and a good aim, that has be (based) upon the correct path. Thus, this (person) is considered mistaken and whoever agrees with him and follows his error will be destroyed, because this is a path of destruction – even though the (person) did not intend to leave (the correct path); rather his quest was (to reach something) good. This is the state of many who initiate newly invented matters in the knowledge of creed. This is not permissible, and they should not adhere to it. The person is not upon correctness. Allah,  The Mighty and Majestic, said:

 وَأَنَّ هَٰذَا صِرَاطِي مُسْتَقِيمًا فَاتَّبِعُوهُ ۖ وَلَا تَتَّبِعُوا السُّبُلَ فَتَفَرَّقَ بِكُمْ عَنْ سَبِيلِهِ

And verily, this is my Straight Path, so follow it, and follow not (other) paths, for they will separate you away from His Path]. [Al-An’am. 153]

Therefore, we reject any path that exits us from the Straight Path even if the one who (calls) to it aims for good and has a good intention. We do not follow him in that while he continues upon his error, eventually leading to destruction, because whoever abandons the correct path in his journey and takes a path of ruin will be destroyed.

As for the second person, it is the one who intends to leave (the correct path). He knows the truth and that what he embarks upon is falsehood, but he intends to leave the truth with the intention of misguiding the people. So, the intention of the first (person) is to bring about benefit for the people, but he did not follow the correct path. The second (person) intended to misguide the people and turn them away from the correct path. Therefore, this one is a devil because the devils take the people away from the Straight Path. (Allah informs us that) Iblees said:

لَأَقْعُدَنَّ لَهُمْ صِرَاطَكَ الْمُسْتَقِيمَ

Surely, I will sit in wait against them (human beings) on Your Straight Path]. [7:16]

He intends to turn them away from it towards the deviated paths. The Prophet,  peace and blessings of Allah be upon him, gave us an example when he drew a straight line and drew other lines on its sides, he then said about the straight line, “This is the path of Allah” and he said about the other lines, “These are the other paths, and on each path is a devil calling to it”. This is a clear example that agrees with what the Shaikh (i.e. Imam Al-Barbahaaree) has stated here. Therefore, the one who takes the people away from the Straight Path (and directs them) to the innovated paths of the innovators (in religious matters) is not one who intends good for them; rather he intends destruction for them. He is a devil – a devil amongst the Jinn or the people. It is obligated to us to be more careful of this (second person) than the first one because this one (i.e. the second) intends to misguide the people.

“He is astray, leading others astray, a rebellious devil”.

Al-Allamah Salih Al-Fawzaan stated:

He is misguided and misguiding others- a rebellious devil, a rebel intending to turn the people away from the Straight Path.

“It is a duty upon those who know of him to warn the people against him and to explain his condition to them so that no one falls into his innovation and is destroyed”.

Al-Allamah Saalih Al-Fawzan commented:

It is not permissible to keep quiet about this one who abandons the truth intentionally; rather it is obligatory to unveil his affair and uncover his vileness until the people are warned about him. It is not to be said that the people are free to hold views, freedom of speech and respecting the views of others, as said at present with regards to respecting the views of others. The matter is not about views, (rather), the matter is about Ittibaa. Allah has outlined a clear path for us, and He told us to adhere to it, when He stated:

وَأَنَّ هَٰذَا صِرَاطِي مُسْتَقِيمًا فَاتَّبِعُوه

And verily, this is my Straight Path, so follow it’ [6:153]

If any person comes to us and wants us to leave this straight path, firstly we reject his statement. Secondly, we clarify and warn the people against him and we do not keep quiet about him; because if we keep quiet about him, the people will be deceived by him, especially if he is an eloquent person with (skillful) writing and education, because the people will be deceived by him and will say, “This one is competent, this one is from the thinkers” as is taking place today. Therefore, the matter is very dangerous. And with regards to this, is a (justification) to refute the one in opposition, as opposed to what those who say, “Abandon the refutations, leave the people, everyone has his views and have respect for him”. Through this (so-called) respect for the views and freedom of speech, the Ummah will be destroyed. The Salaf did not keep quiet about the likes of these people; rather they exposed and refuted them due to their knowledge of the danger upon Ummah. We do not keep quiet about their evil; rather what Allah has revealed must be clarified, otherwise, we will be from those who conceal the truth- those about whom Allah said:

إِنَّ الَّذِينَ يَكْتُمُونَ مَا أَنْزَلْنَا مِنَ الْبَيِّنَاتِ وَالْهُدَىٰ مِنْ بَعْدِ مَا بَيَّنَّاهُ لِلنَّاسِ فِي الْكِتَابِ ۙ أُولَٰئِكَ يَلْعَنُهُمُ اللَّهُ وَيَلْعَنُهُمُ اللَّاعِنُونَ

Verily, those who conceal the clear proofs, evidences and the guidance, which We have sent down, after We have made it clear for the people in the Book, they are the ones cursed by Allah and cursed by the cursers] [2:159]

The matter is not limited to the innovator, rather it is extended to the one who keeps quiet about him (i.e. the one who deliberately keeps quiet while being aware about him). Rebuke and punishment (i.e. warning) are extended to him because it is obligatory to clarify.

An Excerpt from It’haf Al-Qaaree Bit-taleeqaat Alaa Sharh As- Sunnah Lil-Imam Al-Barbahaaree 1/110-115. Slightly paraphrased