Narrated Ibn `Umar: Allah's Apostle said, "A faithful believer remains at liberty regarding his religion unless he kills somebody unlawfully."
Hadith Referenceصحيح البخاري / كتاب الديات / 6862
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة
Explanation & Benefits
Shaykh Abdul Sattar al-Hammad
Hadith Commentary: A believer’s chest remains open and he always has hope for forgiveness, but when he kills someone without just cause, he falls into distress and even the door of forgiveness is closed for him. This is because there is a very severe warning regarding unjustified killing; such a grave warning has not been given for any other crime. For this reason, his religion becomes constricted for him. (Fath al-Bari: 12/233)
Source: Hidayat al-Qari: Commentary on Sahih Bukhari, Urdu, Page: 6862