The Prophet ﷺ said, "Fast when you see it and break your fast when you see it. If it is obscured from you, then complete the count as thirty."
حدثنا يحيى بن سعيد عن شعبة قال حدثنا محمد بن زياد
عن النبي ﷺ قال صوموا لرؤيته وأفطروا لرؤيته فإن غم عليكم فأكملوا العدة ثلاثين
[Shakir: 9520] Its isnad is sahih, it passed previously at 9346 and 9426. [Shakir: 9521] Its isnad is sahih, it is the same hadith as the one before it.