‘Amr bin Yazeed was a friend of Imaam Maalik (rahimahullah) who lived in Egypt. He narrates the following:

I once said to Imaam Maalik (rahimahullah), “O Abu ‘Abdillah! People travel to you from different lands. They wear out their animals and spend their money in coming to you so that they can ask you their masaa’il and benefit from the knowledge of Deen which Allah Ta‘ala has blessed you with. Thereafter, when they ask you their question, you often tell them, ‘I do not know the answer.’”