Bukhari :: Book 3 :: Volume 48 :: Hadith 853
Whenever Allah's Apostle intended to go on a journey, he used to draw lots among his wives and would take with him the one on whom the lot fell. He also used to fix for everyone of his wives a day and a night, but Sauda bint Zam'a gave her day and night to 'Aisha, the wife of the Prophet intending thereby to please Allah's Apostle.
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