The beauty of saying ” I do not know.”

Imam Malik {May Allah have mercy upon him} said:

“The shield of the scholar is to say, ‘I don’t know’, so If he leaves it down, his attacker will strike him.”

{Related by Hafiz Yusuf Ibn Abd al-Barr in his al-Intiqa’  fi Fada’ il at-Thalatha al-Fuqaha}