It is narrated from Masruq (may Allah have mercy on him) that he came to the Mother of the Believers, Sayyidah Aishah (may Allah be pleased with her), on the day about which there is doubt (whether it is of Ramadan). She said to her slave girl: "O girl! Prepare some sawiq (barley mash) for him." Masruq (may Allah have mercy on him) said: "I am fasting." Sayyidah Aishah (may Allah be pleased with her) asked: "Have you started (fasting) ahead of the month?" I said: "No, but I have fasted the whole of Sha'ban, and so it (happened to) coincide with this day." Then Sayyidah Aishah (may Allah be pleased with her) said: "Some people used to start (fasting) ahead of the month and fast before the Prophet (peace and blessings be upon him), so Allah, the Mighty and Majestic, revealed this verse: 'O you who believe, do not put yourselves before Allah and His Messenger.'"
No one narrated this hadith from Abu Kudaynah (may Allah have mercy on him) except Abu Usamah (may Allah have mercy on him).
Hadith Referenceالمعجم الأوسط / باب الألف / 2713
Hadith Gradingمحدثین:إسناده ضعيف لجهالة حبان بن رقيدة
Hadith Takhrij«قال الهيثمي: فيه حبان بن رقيدة وهو مجهول «مجمع الزوائد ومنبع الفوائد، ج 3، ص 148»»