Bismillah hir-Rahman nir-Rahim
Hadith: Musalmaan ko Gaali dena Fisq hai aur Qatl karna Kufr
Abdullah Radiallahu anhu se rivayat hai ki Rasoollallahu Sallallahu Alaihi Wasallam ne farmaya musalman ko gaali dena Fisq (belong to Fasiq) hai aur Qatl karna kufr hai
Sahih Bukhari, Vol 8, 7076
Narrated Abdullah Radiallahu anhu : The Prophet Sallallahu Alaihi Wasallam said,
Abusing a Muslim is Fusuq (evil doing) and killing him is Kufr (disbelief).
Sahih Bukhari, Vol 9, Book 88, No. 197: