The Messenger of Allah said, "Keep careful count of the crescent of Shaban for the sake of Ramadan."
حدثنا مسلم بن حجاج حدثنا يحيى بن يحيى حدثنا أبو معاوية عن محمد بن عمرو عن أبي سلمة
قال رسول الله أحصوا هلال شعبان لرمضان
No references are available.
Its isnad is daif. Daraqutni reported it in 2/163, hadith 2154, from the narration of Imam Muslim, the author of Sahih (Muslim), through this route, and Hakim graded it sahih according to the criteria of Muslim, 1/425, and Dhahabi agreed with him. Abu Muawiya is a mudallis and he narrated it using "an" (without specifying direct hearing).The hadith, "Do not precede the month of Ramadan..." etc., has already occurred at 684, 685, the second one through the route of Yahya bin Abu Kathir.