(16) باب الدَّلِيلِ عَلَى زِيَادَةِ الإِيمَانِ وَنُقْصَانِهِ
Ibn 'Umar reported the Messenger of Allah (May peace be upon him) as saying :
If any believing man calls another believing man an unbeliever, if he is actually an infidel, it is all right ; if not, he will become an infidel. (ID)
Reference (ID): Sunan Abi Dawud 4687 (ID)
In-book reference (ID): Book 42, Hadith 92 (ID)
English translation (ID): Book 41, Hadith 4670 (ID)