Sahih Bukhari

Narrated Al-Qasim bin Abi Bazza:That he asked Sa`id 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."" Sa`id 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