Abdullah bin 'Umar narrated that 'Umar bin al-Khattab said:
I heard the Messenger of Allah ﷺ say: “Allah, may He be glorified and exalted, forbids you to swear by your fathers,` 'Umar said: By Allah, I never swore by them since I heard the Messenger of Allah ﷺ forbid it, and I never uttered (such words) whether I was swearing an oath or describing someone else doing so.