Narrated Jarir bin 'Abdullah
Prophet sallallahu alaihi wa sallam said,"Allah will not be merciful to those who are not merciful to mankind."
Bukhari 9.473

Aur ussey bada zaalim kaun hoga, jise uske Rabb ki ayaat ke zariye se Nasihat ki jaye aur phir wo usse muh pher le.
Quran 32.22