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.' "

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا سُفْيَانُ، عَنْ أَيُّوبَ، عَنْ عِكْرِمَةَ، أَنَّ عَلِيًّا ـ رضى الله عنه ـ حَرَّقَ قَوْمًا، فَبَلَغَ ابْنَ عَبَّاسٍ فَقَالَ لَوْ كُنْتُ أَنَا لَمْ أُحَرِّقْهُمْ، لأَنَّ النَّبِيَّ ﷺ قَالَ " لاَ تُعَذِّبُوا بِعَذَابِ اللَّهِ ". وَلَقَتَلْتُهُمْ كَمَا قَالَ النَّبِيُّ ﷺ " مَنْ بَدَّلَ دِينَهُ فَاقْتُلُوهُ ".