Kathir bin 'Ubaid bin Nmyr كثير بن عبيد بن نمير المذحجي · Marriage (Kitab Al-Nikah)

When Ali married Fatimah, the Prophet (ﷺ) said to him: Give her something. He said: I have nothing with me. He said: Where is your Hutamiyyah (coat of mail).

When Ali married Fatimah, daughter of the Messenger of Allah (ﷺ), he intended to have intercourse with her. The Messenger of Allah (ﷺ) prohibited him to do so until he gave her something. Ali said: I have nothing with me, Messenger of Allah. The Prophet (ﷺ) said: Give her your coat of mail. So he gave her his coat of mail, and then cohabited with her.