Musannaf Ibn Abi Shayba 36:248

'Affan narrated to us, he said: Hammad bin Salamah narrated to us, he said: 'Ata' bin al-Sa'ib informed us, from al-Sha'bi, that a woman gave a sword to her son on the day of Uhud, but he could not bear its weight. So she tied it to his forearm with a leather strap, then she brought him to the Prophet, peace be upon him. She said: "O Messenger of Allah, this is my son fighting for you." The Prophet, peace be upon him, said: "O my son, strike here; O my son, strike here." Then he received a wound and fell. He was brought to the Prophet, peace be upon him, who said: "O my son, perhaps you were distressed?" He said: "No, O Messenger of Allah."