Waail bin Hajar reported,

A man who had killed another was brought to the Messenger of Allah ﷺ, and the victim's heir was granted retaliation against him. He led him away with a rope around his neck, dragging him along.As they were leaving, the Messenger of Allah ﷺ said, "The killer and the killed are both in the Fire."A man went to the heir and reported to him what the Messenger of Allah ﷺ had said, so he released him.Ismail bin Salim said, I mentioned this to Habib bin Abu Thabit, and he said, Ibn Ashwa narrated to me that the Prophet ﷺ had actually asked the heir to pardon him, but he refused.

Muslim 4388

Sahih

و حدثني محمد بن حاتم حدثنا سعيد بن سليمان حدثنا هشيم أخبرنا إسمعيل بن سالم

عن علقمة بن وائل عن أبيه قال

أتي رسول الله ﷺ برجل قتل رجلا فأقاد ولي المقتول منه فانطلق به وفي عنقه نسعة يجرها فلما أدبر قال رسول الله ﷺ القاتل والمقتول في النار فأتى رجل الرجل فقال له مقالة رسول الله ﷺ فخلى عنه قال إسمعيل بن سالم فذكرت ذلك لحبيب بن أبي ثابت فقال حدثني ابن أشوع أن النبي ﷺ إنما سأله أن يعفو عنه فأبى

مسلم 4388صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Qasama, combatants, legal retaliation, and blood money
Chapter
Validity of confession to murder, enabling the victim's guardian to carry out legal retribution, and the recommendation to seek pardon from him
Numbering
Darussalam 4388
Muslim 4388