31.137 http://www.mohammeds-koran.com/texts/hadith/bukhari/31/31.137 http://www.mohammeds-koran.com/@@site-logo/Jihad_Sword_White_Background.png 31.137 Narrated Ibn 'Umar: The Prophet 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."