Musnad Ahmad 27:1612

Sulayman ibn Hayyan narrated to us, from al-Hasan ibn Ubayd Allah, from Sa'd ibn Ubaydah, that he heard Ibn Umar [saying to] a man who was saying, "By the Ka'bah": "Do not swear by other than Allah, for I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'Whoever swears by other than Allah has committed disbelief and shirk.'"