It was narrated that Rifa'ah said:
"I entered upon Mukhtar in his palace and he said: 'Jibril has just left me.' Nothing stopped me from striking his neck (i.e, killing him) but a Hadith that I heard from Sulaiman bin Surad, according to which the Prophet (ﷺ) said: 'If a man trusts you with his life, then do not kill him.' That is what stopped me."
English reference: Vol. 3, Book 21, Hadith 2689
Arabic reference: Book 21, Hadith 2791