Hadith #2143The Book of Fasting · Narrated by ibn Umar, Muhammad bin al-Muthna - al-Zaman محمد بن المثنى أبو موسى - الزمن, Muhammad bin Ja'far Ghandar محمد بن جعفر غندر صاحب الكرابيس, Shu'bah bin al-Hajjaj شعبة بن الحجاج, Uqba bin Hryth al-Tghlby عقبة بن حريث التغلبي الكوفي
“The Messenger of Allah said: The month may be twenty-nine days or it may be thirty. When you see it, then stop fasting, and it is obscured from you (too cloudy), then complete the count.”‘