Ibn Umar (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) heard a man swearing by his father, so he (peace and blessings be upon him) said: "Do not swear by your fathers. Whoever swears, let him swear truthfully; whoever is given an oath by Allah, let him be content; and whoever is given an oath by Allah and is not content, he has nothing to do with Allah."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20723