A hadith and commentary.
The Prophet, peace and blessings of Allah be upon him, said when he was asked about the Hour:
"The one being asked about it knows no more than the one asking."
The commentary:
Imam al-Nawawi, may Allah have mercy on him, stated in his commentary on Sahih Muslim:
"This indicates that it is appropriate for a scholar, a jurist, and others, when asked about something they do not know,
to say, 'I do not know.'
This does not diminish their status;
rather, it serves as evidence of their piety, God-consciousness, and the depth of their knowledge.
I have detailed this with its proofs, supporting evidence, and related matters
in the introduction to Sharh al-Muhadhdhab,
which contains various forms of goodness
that a student of knowledge must be familiar with and study consistently."