Imam Malik's Muwatta, Chapter: The Mudabbar

Yahya related to me from Malik from Ibn Shihab from Safwan ibn Abdullah ibn Safwan that it was said to Safwan ibn Umayya, "Whoever does not do hijra is ruined." So Safwan ibn Umayya went to Madina and slept in the mosque with his cloak as a pillow. A thief came and took his cloak and Safwan grabbed hold of the thief and brought him to the Messenger of Allah, may Allah bless him and grant him peace. The Messenger of Allah, may Allah bless him and grant him peace, said to him, "Did you steal this cloak?" He said, "Yes." So the Messenger of Allah, may Allah bless him and grant him peace, ordered that his hand be cut off. Safwan said to him, "I did not intend this. It is his as sadaqa." The Messenger of Allah, may Allah bless him and grant him peace, said, "Why didn't you do it before bringing him to me?"