Sahih Bukhari
Prophetic Commentary on the Quran (Tafseer of the Prophet (PBUH))
Volume: 006 / Book Number: 060 / Hadith Number: 285
Narrated Al-Qasim bin Abi Bazza:
That he asked Said bin Jubair, "Is there any repentance of the one who has murdered a believer intentionally?" Then I recited to him:--
"Nor kill such life as Allah has forbidden except for a just cause." Said said, "I recited this very Verse before Ibn 'Abbas as you have recited it before me. Ibn 'Abbas said, 'This Verse was revealed in Mecca and it has been abrogated by a Verse in Surat-An-Nisa which was later revealed in Medina."