Musnad Abu Ya'la al-Mawsili 155:208

Ubayd Allah ibn Mu'adh ibn Mu'adh al-'Anbari narrated to us, my father narrated to us, 'Awf narrated to us, from Muhammad ibn Sirin, from Abu Hurayrah, who said: The Messenger of Allah (peace be upon him) said: "Do not swear by your fathers, nor by your mothers, nor by idols. And do not swear by Allah unless you are truthful."