Sayyidah Asma' bint Yazid (may Allah be pleased with her) narrated: A drink was brought to the Prophet (peace and blessings be upon him), and the drink was passed round to all those present. Among them was a man who was fasting. When the drink reached him, the Prophet (peace and blessings be upon him) said to him: "Drink!" It was said: "O Messenger of Allah! This man does not leave any voluntary fast; he fasts continually." The Prophet (peace and blessings be upon him) said: "The one who fasts perpetually has not in reality fasted."
Imam Ahmad and Imam al-Tabarani in al-Mu'jam al-Kabir recorded it, and he (al-Tabarani) reported the wording: "Whoever fasts perpetually has neither fasted nor broken his fast." Its chain contains a narrator, Layth bin Abi Sulaym; he is thiqah (trustworthy), but he is a mudallis (one who conceals defects in the chain).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 5166
Hadith Gradingمحدثین:إسنادہ ضعیف
Hadith Takhrij«اخرجه الطبراني فى المعجم الكبير (179/24) اخرجه احمد فى المسند (455/6) ، أخرجه مسند أحمد برقم: 27029»