Bukhari 3017

Narrated `Ikrima:`Ali burnt some people and this news reached Ibn `Abbas, who said, "Had I been in his place I would not have burnt them, as the Prophet (ﷺ) said, 'Don't punish (anybody) with Allah's Punishment.' No doubt, I would have killed them, for the Prophet (ﷺ) said, 'If somebody (a Muslim) discards his religion, kill him