Musnad Ahmad 28:438

Aswad ibn Amir narrated to us, Abu Bakr—meaning Ibn Ayyash—narrated to us, he said: We entered upon Abu Husayn to visit him, and with us was Asim. He said: Abu Husayn said to Asim: "Do you remember a hadith that Al-Qasim ibn Mukhaymirah narrated to us?" He said: "Yes, he narrated to us one day from Abdullah ibn Amr, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: 'When the Muslim servant becomes ill, it is said to the scribe who writes his deeds: Write for him the like of his deeds when he was free, until I take his soul or set him free.'" Abu Bakr said: "Asim and Abu Husayn both narrated it to us."