It was narrated that Abu Juhaifah said: “I said to 'Ali bin Abu Talib: 'Do you have any knowledge that the people do not have?' He said: 'No, by Allah, we only know what the people know, except that Allah may bless a man with understanding of Qur'an or what is in this sheet, in which are mentioned the rulings on blood money from the Messenger of Allah (ﷺ) and it says that a Muslim should not be killed in retaliation for the murder of disbeliever.'”
It was narrated from 'Amr bin Shu'aib, from his father, from his grandfather, that the Messenger of Allah (ﷺ) said: “A Muslim should not be killed in retaliation for the murder of a disbeliever.”
It was narrated from Ibn 'Abbas that the Prophet (ﷺ) said: ”A believer should not be killed in retaliation for the murder of a disbeliever, and a person who has a treaty should not be killed during the time of the treaty.”