Yahya related to me from Malik from Thawr ibn Zayd ad-Dili from Abdullah ibn Abbas that the Messenger of Allah, may Allah bless him and grant him peace, once mentioned Ramadan and said, "Do not start the fast or break it until you see the new moon. If the new moon is obscured from you, then complete a full thirty days."
Muwatta Malik Book 18, Hadith 3
← Previous Hadith Yahya related to me from Malik from Abdullah ibn Dinar from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, said, "A month has twenty-nine days in it. Do not start the fast or break it until you see the new moon. If the new moon is obscured from you, then work out (when it should be)."

Muwatta Malik Book 18, Hadith 2 Next Hadith → Yahya related to me from Malik that he had heard that once in the time of Uthman ibn Affan the new moon had been seen in the afternoon and Uthman did not break his fast until evening had come and the sun had set.

Yahya said that he had heard Malik say that some one who sees the new moon of Ramadan when he is on his own should start the fast and not break it if he knows that that day is part of Ramadan. He added, "Some one who sees the new moon of Shawwal when he is on his own does not break the fast, because people suspect the reliability of someone among them who breaks the fast. Such people should say, when they sight the new moon, 'We have seen the new moon.' Whoever sees the new moon of Shawwal during the day should not break his fast but should continue fasting for the rest of that day. This is because it is really the new moon of the night that is coming ."

Yahya said that he heard Malik say, "If people are fasting on the day of Fitr thinking that it is still Ramadan and then definite evidence comes to them that the new moon of Ramadan had been seen one day before they began to fast and that they are now into the thirty- first day, then they should break the fast on that day at whatever time the news comes to them. However, they do not pray the id prayer if they hear the news after the sun has begun to decline."

Muwatta Malik Book 18, Hadith 4