سنن النسائي

It was narrated from 'Alqamah bin Wa'il that his father said: "I was sitting with the Messenger of Allah (ﷺ) when a man came with a string around his neck and said: 'O Messenger of Allah, this man and my brother were digging a hole, and he raised his pickax and struck his companion in the head, Killing him. 'The Prophet (ﷺ) said: 'Forgive him,' but he refused and said: 'O Prophet of Allah, this man and my brother were digging a whole, and he raised his pickax and struck his companion in the head, killing him.' The Prophet (ﷺ) said: 'Forgive him,' but he refused, then he stood up and said: 'O Messenger of Allah, this man and my brother were digging a hole, and he raised his pickax and struck his companion in the head, killing him.' The Prophet (ﷺ) said: 'Forgive him,' but he refused. He (the prophet) said: 'Go, but if you kill him, you will be like him. So he took him out, and they called out to him: Didn't you hear what the Messenger of Allah (ﷺ) said?' So he came back and he said: 'If I kill him will I be like him?' He said: 'Yes. Forgive him.' Then he went out, dragging his string, until he disappeared from our view."