مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1870
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from ‘Ikrimah that ‘Ali burned some people who apostatized from Islam. News of that reached Ibn "Abbas and he said: I would not have burned them with fire. The Messenger of Allah (ﷺ) said: "Do not punish people with the punishment of Allah." I would have executed them, because the Messenger of Allah (ﷺ) said: “Whoever changes his religion, execute him." News of that reached ‘Ali (رضي الله عنه) and he said: Woe to the son of the mother of Ibn "Abbas.
Musnad Ahmad 1871Sahih (Darussalam) [ al-Bukhari (3017)]