1341 - Abu 'Abd Allah narrated to us, he said: I heard Yahya say: "I have not encountered anyone among our companions, nor has it reached me, except [that they practiced] al-istithna' (the making of exception in faith by saying 'Insha'Allah')." And Yahya said: "Faith is speech and action." Yahya said: "Sufyan used to disapprove of saying 'I am a believer,' and Yahya deemed the concept of increase and decrease [in faith] to be sound following him."