Weak Narration Concerning the prohibition of Helping to Kill a Muslim

Firstly:  

This hadeeth was
narrated by Ibn Majah (2620) and al-‘Aqeeli in al-Du’afa (457) and
al-Bayhaqi in al-Sunan (8/22). It is a da’eef (weak) hadeeth which is not
soundly narrated from the Prophet (peace and blessings of Allah be upon
him). Imam Ahmad said: This hadeeth is not saheeh. 

Indeed, Abu Hatim
ruled it to be mawdoo’ (fabricated), and al-Thahabi agreed with him. Ibn
al-Jawzi narrated it in al-Mawdoo’at (2/104). Ibn Hibban said: This is a
mawdoo’ (fabricated) hadeeth which has no basis. 

Ibn Hajar and
al-Munthiri said: (This is) a very weak hadeeth. Al-Zayla’i said: it is a
weak (da’eef) hadeeth. 

Al-Albani
mentioned it in Da’eef Sunan Ibn Majah and said: (it is) very weak. 

Secondly: 

Even though this
hadeeth is weak, there is no doubt that helping to kill a Muslim unlawfully
is a major sin. 

Al-‘Izz ibn ‘Abd
al-Salam (may Allah have mercy on him) said in his book al-Qawa’id: 

If you want to
know the difference between a minor sin and a major sin, then compare the
consequences of the sin with the consequences of a major sin as stated in
the texts. If it is less than the least consequences of a major sin, then it
is a minor sin. If it is equal to or greater than the least consequences of
a major sin, then it is also a major sin. Whoever insults the Lord, may He
be glorified, or His Messenger (peace and blessings of Allah be upon him),
or mocks the Messengers, or disbelieves in one of them, or throws filth at
the Ka’bah, or throws the Mus-haf (copy of the Quran)  into the garbage –
these are major sins, even though the sharee’ah does not state clearly that
they are major sins. Similarly, if a person holds down a chaste woman for
another to commit zina (adultery) with her, or holds down a Muslim for him
to kill him, the evil consequences of these acts are undoubtedly greater
than the consequences of consuming the wealth of an orphan, even though that
is also a major sin. Similarly if a person guides the kuffar (non-Muslims)
to the weak points of the Muslims, even though he knows that they will
destroy the Muslims as a result of his help and will take their women and
children captive, and plunder their wealth, then this is more serious than
his running away from the battle field with no excuse, even though that is a
major sin. Similarly if he tells a lie about a person for which he knows
that person will be killed, then it is a major sin, but telling a lie which
will result in a date being taken away from him, is not a major sin.”  

Helping a kafir to
kill a Muslim may constitute kufr (disbelief) in some cases. The scholars
mentioned things that nullify a person’s Islam, one of which is supporting
the mushrikeen (polytheists) and helping them against the Muslims. See
question no.

33691. 

Thirdly: 

It is not
permissible for anyone to take the matter of attributing hadeeth to the
Prophet (peace and blessings of Allah be upon him) lightly. He (peace and
blessings of Allah be upon him) said: “Whoever tells lies about me, it is
not like telling lies about anyone else. Whoever tells lies about me
deliberately, let him take his place in Hell.” Narrated by al-Bukhari, 1291;
Muslim, 4. 

And he (peace and
blessings of Allah be upon him) said: “Whoever narrates a hadeeth from me
which is known to be false, he is one of the liars.” Narrated by Muslim in
the introduction to his Saheeh. 

And al-Nawawi
said: 

[This hadeeth has
been narrated in two versions, one of which says al-kathibayn (the two liars
– dual form) and the more well-known version which says al-kathibeen (the
liars – plural).] Al-Qadi ‘Iyad said: The version which we have says
al-kathibeen (plural) and Abu Na’eem al-Asbahani narrated it in his book
al-Mustakhraj ‘ala Saheeh Muslim from the hadeeth of Samurah, where it says
al-kathibayn, in the dual form. Some of the imams said that the word yura
[translated above as “known to be” as yara [meaning “knowing (himself).” Or
it could mean “thinking [that it is false].” In this case the hadeeth means
that the person becomes a sinner only when he himself knows or thinks that
what he is narrating from the Prophet (peace and blessings of Allah be upon
him) is a lie. But if he did not know or think that it was a lie, then there
is no sin on him if he narrated it, even if others think that it is false,
or know that to be the case.  But what we may conclude from this hadeeth is
that lying is strongly condemned, and that whoever thinks that what he is
narrating is most likely false, but still narrates it, is a liar. How can he
not be a liar when he is narrating something that did not happen? 

If a person does
not have sufficient knowledge to be able to distinguish between a saheeh
(authentic) hadeeth and a da’eef (weak) one, then he should ask the scholars
who are specialized in this field, and refer to the comments of the imams
and scholars that are compiled in books, in accordance with the words of
Allah (interpretation of the meaning): 

“So ask of those who know the Scripture, if you know not.” [16:43].