question #3 Sahih al-Bukhari 7355, Book 96, Hadith 82 : What role does the testimony of companions play in confirming or denying claims in Islam?

I saw Jabir bin `Abdullah swearing by Allah that Ibn Sayyad was the Dajjal. I said to Jabir, “How can
you swear by Allah?” Jabir said, “I have heard `Umar swearing by Allah regarding this matter in the
presence of the Prophet (ﷺ) and the Prophet (ﷺ) did not disapprove of it.”