Is there any source for the famous story of Bishr Al-Hafi’s picking up a piece of paper on which Bismillah was and perfuming it?
Yes, Imam Ibn Qudamah (rahimahullah) has recorded this in his book, Kitabut Tawwabin, pg. 210, number: 79.
Because of him showing respect to the name of Allah, he was guided.
And Allah Ta’ala Knows best,
Answered by: Moulana Muhammad Abasoomar