Waail reported,

I was present with the Messenger of Allah ﷺ when the killer was brought, led by the victim's heir with a rope around him.The Messenger of Allah ﷺ asked the victim's heir, "Will you pardon him?"He answered, "No."He asked, "Will you take the blood-money?"He answered, "No."He asked, "Then you will kill him?"He answered, "Yes."He said, "Take him away."When he took him away and turned to leave, the Messenger of Allah ﷺ called him back and asked him, "Will you pardon him?"He answered, "No."He asked, "Will you take the blood-money?"He answered, "No."He asked, "Then you will kill him?"He answered, "Yes."He said, "Take him away."At that point the Messenger of Allah ﷺ said, "If you pardon him, he will bear his own sin and the sin of your companion."So he pardoned him and let him go. I saw him afterwards dragging his rope behind him.

Nasai 4728

Sahih

أخبرنا محمد بن بشار قال حدثنا يحيى بن سعيد عن عوف بن أبي جميلة قال حدثني حمزة أبو عمر العائذي قال حدثنا علقمة بن وائل

عن وائل قال

شهدت رسول الله ﷺ حين جيء بالقاتل يقوده ولي المقتول في نسعة فقال رسول الله ﷺ لولي المقتول أتعفو قال لا قال أتأخذ الدية قال لا قال فتقتله قال نعم قال اذهب به فلما ذهب به فولى من عنده دعاه فقال له أتعفو قال لا قال أتأخذ الدية قال لا قال فتقتله قال نعم قال اذهب به فقال رسول الله ﷺ عند ذلك أما إنك إن عفوت عنه يبوء بإثمه وإثم صاحبك فعفا عنه وتركه فأنا رأيته يجر نسعته

النسائي 4728صحيح
Contents
Reference
Commentary
Ayat
Collection
Sunan Nasai Sughra
Book
Sworn testimony
Chapter
Disagreement among narrators of the hadith of Alqama bin Waail regarding this
Numbering
Darussalam 4728
Nasai 4728