Sufyaan ath-Thawree used to spend the nights and the days
crying and the people used to ask him,
"Why do you cry, is it due to the fear of Allh?
He said,
"No."
They said,
"Is it due to the fear of the Hellfire?"
He said,
"No. It is not the fear of Hellfire that makes
me cry, what makes me cry is that I have been
worshipping Allh all these years and doing
scholarly teaching, and I am not certain that
my intentions are purely for Allah."