قال سمرة بن جندب رضي الله عنه   ﻣﻦ سَرَّهُ ﺃﻥ ﻳﻌﻠﻢ ﻣﻜﺎﻥ اﻟﺸﻴﻄﺎﻥ ﻣﻨﻪ ﻓﻠﻴﻨﻈﺮﻩ ﻋﻨﺪ ﻋﻤﻞ اﻟﺴﺮ الزهد   لابن المبارك      ٨٤٩  
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