It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "No man will leave faith except by denying the very thing through which he entered it."
No one narrated this hadith from Mis'ar (may Allah have mercy on him) other than Isma'il bin Yahya al-Taymi (may Allah have mercy on him), and Muhammad bin Harb (may Allah have mercy on him) is alone in narrating it from him.
Hadith Referenceالمعجم الأوسط / باب العين / 4433
Hadith Gradingمحدثین:موضوع، فيه إسماعيل بن يحيى التيمي وضاع
Hadith Takhrij«قال الهيثمي: فيه إسماعيل بن يحيى التيمي وهو وضاع «مجمع الزوائد ومنبع الفوائد، ج 1، ص 106»»