Hadith 4:743
Ubaydah ibn Humayd narrated to us, from al-Aswad ibn Qays, from Sa’id ibn ‘Amr, that ‘Abdullah ibn ‘Umar narrated to them that the Prophet (may Allah bless him and grant him peace) said: "We are an unlettered nation; we do not write and we do not calculate. The month is like this and like this," and he struck [his fingers] a third time and clenched his thumb. ‘A’ishah said: "May Allah forgive Abu ‘Abd al-Rahman! The Prophet (may Allah bless him and grant him peace) only stayed away from his wives for a month, then he came down after twenty-nine [days]. They said: 'O Messenger of Allah, you swore an oath for a month.' He said: 'The month can be twenty-nine.'"
حدثنا عبيدة بن حميد عن الأسود بن قيس عن سعيد بن عمرو أن عبد الله بن عمر حدثهم أن النبي صلى الله عليه وسلم قال انا أمة أمية لا تكتب ولا تحسب الشهر كذا وكذا وضرب الثالثة وقبض الابهام فقالت عائشة غفر الله لأبي عبد الرحمن إنما هجر النبي صلى الله عليه وسلم نساءه شهرا فنزل لتسع وعشرين فقالوا يا رسول الله إنك آليت شهرا فقال إن الشهر يكون تسعا وعشرين