The Messenger of Allah ﷺ caught up with Umar during one of his journeys while Umar was saying, "By my father, by my father." He said, "Allah forbids you from swearing by your fathers. Whoever swears must swear by Allah, otherwise let him remain silent."
حدثنا سفيان عن إسماعيل بن أمية عن نافع
أدرك رسول الله ﷺ عمر وهو في بعض أسفاره وهو يقول وأبي وأبي فقال إن الله ينهاكم أن تحلفوا بآبائكم فمن كان حالفا فليحلف بالله وإلا فليصمت
Its isnad is sahih. Ismail bin Umaya, his reliability was already established at 1552, and we add here that Bukhari gave him a biographical entry in al-Kabir 1/1/345-346, saying, "He heard from Nafi, Zuhri, and Saeed Maqburi." The hadith is an abridgment of 4523 and 4548.