Sahih al-Bukhari Book 65, Hadith 286
I asked Ibn `Abbas about Allah's saying:--
'.. this reward is Hell Fire.' (4.93) He said, "No repentance is accepted from him (i.e. the murderer of a
believer)." I asked him regarding the saying of Allah:
'Those who invoke not with Allah any other god.' ...(25.68)
He said, "This Verse was revealed concerning the pagans of the pre-lslamic period."
The people of Kufa differed as regards the killing of a believer so I entered upon Ibn `Abbas (and asked him) about that. Ibn `Abbas said, "The Verse (in Surat-An-Nisa', 4:93) was the last thing revealed in this respect and nothing cancelled its validity."
Ibn Abza said to me, "Ask Ibn `Abbas regarding the Statement of Allah: 'And whoever murders a believer intentionally, his recompense is Hell.' (4.69) And also His Statement: '...nor kill such life as Allah has forbidden, except for a just cause .....except those who repent, believe, and do good deeds.' " (25.68-70) So I asked Ibn `Abbas and he said, "When this (25.68-69) was revealed, the people of Mecca said, "We have invoked other gods with Allah, and we have murdered such lives which Allah has made sacred, and we have committed illegal sexual intercourse. So Allah revealed: 'Except those who repent, believe, and do good deeds and Allah is Oft-Forgiving, Most Merciful.' (25.70)