I do not know

Reference: Siyar A’laam an-Nubalaa – Volume 8, Page 48

Imaam Maalik said he heard ‘Abdullaah ibn Yazeed ibn Hurmuz say:

It is befitting for the scholar to bequeath his companions the term ‘I do not know’, so it becomes a principle to which they seek refuge [from the danger of speaking without knowledge].

He is a graduate of the Islaamic University of Madeenah, having graduated from the Institute of Arabic Language, and later the Faculty of Sharee'ah in 2004. He currently resides in Birmingham, UK.