Is the tradition narrated from Umar, "And Umar asked a man about something, and he said, 'Allah knows best,' so Umar said, 'We have been disgraced if we do not know that Allah knows best. If one of you is asked about something, if he knows it, he should say it, and if he does not know it, he should say, "I have no knowledge of that,"'" authentic, and is the prohibition of saying "Allah knows best" understood from it?

We have not found any trace of "Allah and His Messenger know best" authentically attributed to Umar. Rather, what is established from him and from the Companions, such as Ali and Ibn Mas'ud, and even the Prophet, peace and blessings be upon him, is that they would say "Allah knows best" when answering about matters they did not know, as in the Hadith (definition) of Jibreel and other narrations, in order to avoid affectation.