Is there a hadith which mentions that one loses one's Imaan if one speaks while the Athaan is being called?

Answer

The Shariah prescribes a certain act of ibaadat whilst the Athaan is being recited. It is Sunnatul Muakkadah to remain silent and respond to the Athaan. This is the instruction of Rasulullah (sallallahu alayhi wasallam). Some Fuqaha have mentioned that one's Imaan can be in jeopardy if one does not observe the respect of the Athaan and on the contrary engages in conversation. There is no Hadith which mentions that one loses one's Imaan, nevertheless, it is sinful to engage in conversation during the Athaan.