Sunan al-Nasa'i The Book of Fasting 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.”‘ https://parallelquran.com/hadith/sunan-al-nasai-2143/