Ibn Majah

Explanation:
That is, whoever fabricates lies against me should be prepared to enter Hell.

Hadith Commentary:
1.
The respected preachers, in the heat of their oratory, sometimes say many things that are completely incorrect, and then attribute them to the Messenger of Allah sallallahu alayhi wa sallam, that is, these incorrect statements are presented as hadith.
Imam Bukhari rahimahullah’s purpose is to emphasize that attributing anything to the Messenger of Allah sallallahu alayhi wa sallam requires complete certainty, utmost caution, and verification. If the reins of caution slip from one’s hands, then the situation arises where good deeds are wasted and sin becomes inevitable.
In this regard, it is understood from this narration of Ali radi Allahu anhu that for the one who lies upon the Messenger of Allah sallallahu alayhi wa sallam, there is Hellfire.
Another meaning is that, compared to lying upon the Messenger of Allah sallallahu alayhi wa sallam, one should rather accept entering the Fire, but never lie upon him.
And Allah knows best.
2.
This warning encompasses every kind of lie. Those who narrate baseless traditions in the chapters of encouragement and warning (targhib wa tarhib) also fall under the scope of this warning.
In reality, these people hold the view of leniency in this matter, that if someone narrates a fabricated tradition with the intention of promoting the religion and benefiting others, then not only is it permissible, but it is considered a commendable act.
Their argument is that in the hadith, (كَذَبَ عَلَىَّ) is used. After كَذَبَ, the preposition عَلٰى is used for harm; if the intention is benefit instead of harm, then there is no issue.
But this is a sign of ignorance of the Arabic language. Do they not know that lying in religious matters is, in fact, a form of lying upon Allah Himself, and lying upon Allah is absolutely forbidden, whether it pertains to encouragement and warning or to the actual rulings of the religion? These people also present a narration as evidence that “whoever lies in order to mislead.”
Their intent is that if the purpose of lying is to spread misguidance, then the warning applies, but if the purpose is not to spread misguidance, then the warning does not apply.
This reasoning is incorrect for several reasons.
(1)
The noble hadith scholars have differed regarding whether this hadith of Bazzar is connected (mawsul) or disconnected (mursal).
Dar Qutni and Imam Hakim rahimahullah have given preference to its being mursal, and a mursal narration is not a valid proof. The lam in (لِيُضِلَّ) is not for causation, but for consequence, as in the noble verse:
﴿فَمَنْ أَظْلَمُ مِمَّنِ افْتَرَىٰ عَلَى اللَّهِ كَذِبًا لِّيُضِلَّ النَّاسَ بِغَيْرِ عِلْمٍ﴾ “Who is more unjust than one who invents a lie against Allah so that he may mislead people without knowledge.” (Al-An’am: 6/144)
(2)
In this verse, the lam in (لِيُضِلَّ) is also brought for warning about the outcome, meaning that the result of inventing a lie against Allah is nothing but the spreading of misguidance. Therefore, just as it is forbidden to fabricate lies against Allah,
likewise, it is also impermissible to fabricate lies against the Messenger of Allah sallallahu alayhi wa sallam.
(Fath al-Bari: 1/264)

Hadith Commentary: Benefits and Issues:
«كذب على النبى صلى الله عليه وسلم»
refers to attributing one's own or someone else's statement to the Messenger of Allah (sallallahu alayhi wa sallam). This does not mean that it is permissible to fabricate hadith in support of the Shariah, or for the sake of encouragement or deterrence, in favor of the Prophet (sallallahu alayhi wa sallam). For to declare as his (sallallahu alayhi wa sallam) statement something which he did not say is itself a lie.

Explanation:
Note:
In the chain of narration, Sufyan ibn Waki‘ is weak,
but the final words of the hadith
«مَنْ كَذَبَ عَلَيَّ مُتَعَمِّدًا فَلْيَتَبَوَأْ مَقْعَدَهُ مِنَ النَّارِ»
are authentic and mutawatir through other chains,
see: Hadith numbers 2660, 2659, and 2661.

Commentary:
➊ Just as fabricating a false hadith is forbidden (haram) and a major sin (kabirah), in the same way, transmitting this fabricated hadith to others is also a grave crime. The one who narrates such a hadith is a partner in sin with the one who fabricated it, therefore he too is deserving of the same warning that has been mentioned regarding the fabricator of the hadith, that is, he is of the people of Hellfire.

➋ The wording of this hadith in «الْكَاذِبَيْنِ» has been recited in two ways: in the dual form «الْكَاذِبَيْنِ» and in the plural form «الْكَاذِبِيْنَ». The above translation has been done according to the dual form. According to the plural form, the translation will be: "He too is one of the liars among the liars." This difference does not affect the fundamental issue.

➌ By these two liars are meant the two claimants of prophethood: Musaylimah the Liar in Yamamah (Najd) and Aswad al-Ansi in Yemen. Both claimed prophethood during the lifetime of the Messenger of Allah (sallallahu alayhi wa sallam). Therefore, whoever fabricates a hadith, it is as if he has claimed that he is a prophet, because just as the Qur'an is revelation (wahy), hadith is also, in a sense, revelation, as it too is inspired by Allah. If the plural meaning is taken, it would mean that whoever claims prophethood until the Day of Judgment will also be among them. In one hadith, the Prophet (sallallahu alayhi wa sallam) mentioned thirty liars and impostors (false prophets) who will appear before the Day of Judgment [مسند احمد: 104/2], and the one who fabricates a false narration has been counted among them.

➍ It is permissible to narrate such a report in order to warn people, so that they are not deceived by it and do not act upon it, because in this case the intention is not to deceive, but rather to protect from deception.