I would like to ask a question that is important for me.
In some book (probably 'The Seven Contemplations of Insight' by
Venerable Mahaathera Matara Sri ~Naa.naaraama), I have read a story
about Channa, who, allegedly skipping the preparatory stage of
'discerning mind-and-matter', went right to contemplating
impermanence, and was so overwhelmed by experience of anatta
(not-self), that he run around shouting 'I'm annihilated!'
If someone would kindly indicate me the exact source of this story in
the suttas, I will be more than grateful.