Sayyiduna Abu Hurayrah (may Allah be pleased with him) reports that the Prophet (peace and blessings be upon him) said: "Fasting is a shield and a strong fortress for protection from Hell."
Ahmad recorded it. I say: It is also recorded in the Sahih, but it does not contain the words: "a strong fortress for protection from Hell." Its chain is hasan (good).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 5076
Hadith Gradingمحدثین:إسنادہ حسن۔
Hadith Takhrij«اخرجه احمد فى المسند (402/2) ، أخرجه مسند أحمد برقم: 8972، وأخرجه سنن الدارمي برقم: 1771»