Mukhtasar Bukhari

Narrated by Sayyiduna Ibn Umar (may Allah be pleased with them both) from the Noble Prophet (peace and blessings be upon him) that he (peace be upon him) said: "Listen! Whoever wants to swear an oath should not swear by anyone except Allah. The people of Quraysh used to swear by their forefathers." (Because of this) he (peace be upon him) said: "Do not swear by your forefathers."

Narrated Abu Huraira (may Allah be pleased with him): The Prophet (peace and blessings of Allah be upon him) said: "The truest word spoken by a poet is the saying of Labid (ibn Rabi'ah ibn 'Amir): 'Everything except Allah will perish.' And (the poet of the pre-Islamic era) Umayyah bin Abi al-Salt was close to becoming a Muslim."