Hadith 300:8
Musa narrated to us, he said: Muhammad ibn Jabir narrated to us, from Qays ibn Talq, from his father, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When you see the crescent, then fast, and when you see it, then break your fast. But if it is obscured from you, then complete the count."
حدثنا موسى، قال: حدثنا محمد بن جابر، عن قيس بن طلق، عن أبيه قال: قال رسول الله صلى الله عليه وسلم: " إذا رأيتم الهلال فصوموا، وإذا رأيتموه فأفطروا، فإن أغمي عليكم فأتموا العدة "