Admit your lack of knowledge on certain matters instead of pretending or fabricating things which don't exist.

This hadith is about the importance of admitting ignorance when one does not have knowledge on a certain matter. It is narrated by Al-Bukhari that Masruq visited Abdullah bin Mas’ud and he said to them, “O people! He who has the knowledge of any matter may convey it to the others. And he who has no knowledge, thereof, should say ‘Allahu a’lam (Allah knows better).” This statement encourages us to be honest about our lack of knowledge in certain matters and admit that we do not know rather than pretending or fabricating things which do not exist. Allah said this same thing in the Qur’an when He told His Prophet Muhammad ﷺ “Say (O Muhammad ﷺ): 'No wage do I ask of you for this (the Qur'an), nor am I one of the Mutakallifun (those who pretend and fabricate things which do not exist).'" By admitting our ignorance, we are showing humility and respect for Allah's power as only He truly knows all matters.