Sayyiduna Adi bin Hatim (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "When Ramadan comes, fast thirty days of Ramadan, unless you see the new crescent before that, in which case the matter is different."
Al-Tabarani recorded it in al-Mu'jam al-Kabir. Its chain contains a narrator, Mujalid bin Sa'id, whom al-Nasa'i (may Allah have mercy on him) declared thiqah (trustworthy), while a group of scholars declared him da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 4805
Hadith Gradingمحدثین:إسنادہ ضعیف
Hadith Takhrij«اخرجه الطبراني فى المعجم الكبير (78/17) اخرجه احمد فى المسند (377/4) ، أخرجه شرح معاني الآثار برقم: 2541»