(592) بَابُ الْقَائِلَةِ
As-Sa'ib ibn Yazid said, "'Umar, may Allah be pleased with him,used to pass by us in the middle of the day - or near to it - andsay, 'Get up and take a midday nap. Any time spent here after this is forshaytan.'" (ES)
Reference (ES): Al-Adab Al-Mufrad 1239 (ES)
In-book reference (ES): Book 52, Hadith 2 (ES)
English translation (ES): Book 52, Hadith 1239 (ES)