question #3 Sahih al-Bukhari 6647, Book 83, Hadith 26 : What are the implications of swearing by entities other than Allah in Islam?

I heard `Umar saying, “Allah’s Messenger (ﷺ) said to me, ‘Allah forbids you to swear by your fathers.”
`Umar said, “By Allah! Since I heard that from the Prophet (ﷺ) , I have not taken such an oath, neither
intentionally, nor by reporting the oath of someone else.”