Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 756
Abu Huraira reported: The Apostle (may peace be upon him) said When the call to prayer is made, Satan runs back and breaks wind so as not to hear the call being made, and when the call is finished. he turns round. When Iqama is proclaimed he turns his back, and when it is finished he turns round to distract a man, saying: Re- member such and such; remember such and such, referring to something the man did not have in his mind, with the result that he does not know how much he has prayed.