Musnad Abu Ya'la al-Mawsili 147:54

'Abd al-A'la ibn Hammad al-Narsi narrated to us, Hammad narrated to us, from Sinan Abu Rabi'ah, from Anas, that the Messenger of Allah (may Allah bless him and grant him peace) said: "If Allah tests the servant with a trial in his body, He says to the angel: 'Write for him his righteous deeds that he used to perform.' If He heals him, He washes him and purifies him; and if He takes his soul, He forgives him and has mercy upon him."