Jami` at-Tirmidhi 1407

Narrated Abu Hurairah:"A man was killed during the time of the Messenger of Allah (ﷺ), so the killer was brought to the man's guardian. The killer said: 'O Messenger of Allah! By Allah! I did not mean to kill him.' So the Messenger of Allah (ﷺ) said: 'Then if what he is saying is true, and you kill him, you would enter the Fire.' So he let the man go." He said: "His hands were bound behind him with a Nis'ah." He said: "So he left, dragging his Nis'ah." [He said:] "So he was called Dhan-Nis'ah