Sayyidina Abu Hurayrah (RA) reported that the Prophet (SAW) said, “Beware! He, who kills a mu’ahadah who is in Allah’s protection and His Messenger’s (SAW) protection, has violated Allah’s protection. He will not experience the fragrance of Paradise, though its fragrance can be sensed at a distance of seventy years’ journey.”
[Ibn e Majah 2687]