"Narrated Ibn `Umar:\n\nI heard Allah's Messenger (ﷺ) saying, 'When you see the crescent (of the month of Ramadan), start fasting, and when you see the crescent (of the month of Shawwal), stop fasting; and if the sky is overcast (and you can't see it) then regard the month of Ramadan as of 30 days.'\n\nNarrated `Abdullah bin `Umar:\n\nAllah's Messenger (ﷺ) mentioned Ramadan and said, 'Do not fast unless you see the crescent (of Ramadan), and do not give up fasting till you see the crescent (of Shawwal), but if the sky is overcast (if you cannot see it), then act on estimation (i.e. count Sha'ban as 30 days).'\n\nNarrated `Abdullah bin `Umar`:\n\nAllah's Messenger (ﷺ) said, 'The month (can be) 29 nights (i.e. days), and do not fast till you see the moon, and if the sky is overcast, then complete Sha'ban as thirty days.'\n\nNarrated Ibn `Umar:\n\nThe Prophet (ﷺ) said, 'The month is like this and this,' (at the same time he showed the fingers of both his hands thrice) and left out one thumb on the third time.\n\nNarrated Abu Huraira:\n\nThe Prophet (ﷺ) or Abul-Qasim said, 'Start fasting on seeing the crescent (of Ramadan), and give up fasting on seeing the crescent (of Shawwal), and if the sky is overcast (and you cannot see it), complete thirty days of Sha'ban.'\n\nNarrated Um Salama:\n\nThe Prophet (ﷺ) vowed to keep aloof from his wives for a period of one month, and after the completion of 29 days he went either in the morning or in the afternoon to his wives. Someone said to him 'You vowed that you would not go to your wives for one month.' He replied, 'The month is of 29 days.'\n\nNarrated Anas:\n\nAllah's Messenger (ﷺ) vowed to keep aloof from his wives for one month, and he had dislocation of his leg. So, he stayed in a Mashruba for 29 nights and then came down. Some people said, 'O Allah's Messenger (ﷺ)! You vowed to stay aloof for one month,' He replied, 'The month is of 29 days.'\n\nNarrated Abu Bakra:\n\nThe Prophet (ﷺ) said, 'The two months of `Id i.e. Ramadan and Dhul-Hijja, do not decrease (in superiority).'\n\nNarrated Ibn `Umar:\n\nThe Prophet (ﷺ) said, 'We are an illiterate nation; we neither write, nor know accounts. The month is like this and this, i.e. sometimes of 29 days and sometimes of thirty days.'\n\nNarrated Abu Huraira:\n\nThe Prophet (ﷺ) said, 'None of you should fast a day or two before the month of Ramadan unless he has the habit of fasting (Nawafil) (and if his fasting coincides with that day) then he can fast that day.'"