Narrated Abu Bakr ibn Abi Shaybah, narrated Ghandar, from Shu'bah; and narrated Muhammad ibn al-Muthanna and Ibn Bashshar—Ibn al-Muthanna said: narrated Muhammad ibn Ja'far, narrated Shu'bah, from al-Aswad ibn Qays, who said: I heard Sa'id ibn 'Amr ibn Sa'id that he heard Ibn 'Umar, may Allah be pleased with them both, narrating from the Prophet, peace and blessings be upon him, who said: "We are an unlettered nation; we do not write, nor do we calculate. The month is like this, and like this, and like this"—and he folded his thumb on the third time—"and the month is like this, and like this, and like this," meaning a full thirty days.