I met thirty of the companions of Muhammad (Sallalaahu alaihi wa Sallam) ..

Imam Bukhari mentioned on the authority of Ibn Abi Maleeka that he said:

I met thirty of the companions of Muhammad (Sallalaahu alaihi wa Sallam), every one of them fears for himself from hypocrisy

The Criterion Between The Allies Of the Merciful & The Allies Of the Devil , Ibn Taimiyyah, Chapter 3