Musnad Abu Ya'la al-Mawsili 113:12

Ishaq narrated to us, Abd al-Warith narrated to us, from Ayyub, from Abu Qilabah, who attributed it (to the Prophet), he said: "If one of you becomes drowsy during prayer, let him leave and sleep." Ya'qub ibn Ibrahim al-Dawraqi narrated to us, Muhammad ibn Abd al-Rahman al-Tafawi narrated to us, from Ayyub, from Qilabah, from Anas, from the Prophet, peace be upon him, he said: "If one of you becomes drowsy in his prayer, let him leave and sleep." Ja'far ibn Mihran narrated to us, Abd al-Warith narrated to us, from Ayyub, from Abu Qilabah, who attributed it (to the Prophet), he said: "If one of you becomes drowsy during prayer, let him leave and sleep."