The Messenger of Allah ﷺ said, "When the call to prayer is made, Satan turns and flees, passing wind so that he does not hear the call. When the call is finished, he comes back. Then when the iqamah is announced, he turns away again, and once the iqamah is completed, he returns and slips between a man and his own self, whispering, 'Remember this, remember that,' bringing to mind things the man had not been thinking of, until the man no longer knows how many units of prayer he has performed."
إن رسول الله ﷺ قال: إذا نودي للصلاة أدبر الشيطان له ضراط حتى لا يسمع النداء، فإذا قضي النداء أقبل. حتى إذا نوب بالصلاة أدبر، حتى إذا قضي التثويب أقبل حتى يخطر بين المرء ونفسه، يقول: أذكر كذا أذكر كذا، لما لم يكن يذكر، حتى يظل الرجل إن يدري كم صلى.
Malik related it in "Prayer" (6) from Abu Zinad, from Aaraj, from Abu Hurairah, and he related the hadith with this wording. Bukhari related it through Malik's route in "Adhan" (607), except that he said at the end, "until the man remains not knowing how many units he has prayed." He also related it through another route from Abu Salama, from Abu Hurairah, similarly, adding at the end of the hadith, "so if one of you does not know whether he has prayed three or four, let him perform two prostrations while sitting" (1231, 3285).Muslim related it in "Prayer" (19/389) from Qutayba bin Saeed, who said, Mughira (meaning Hizami) narrated to us from Abu Zinad, similarly, and he said at the end, "until the man remains not knowing how many units he has prayed." He also related it through the route of Abdul-Razzaq, from Mamar, from Hammam bin Munabbih, from Abu Hurairah, and in it, "until the man remains unaware of how he prayed." Here "in" is the negating particle meaning "not," as in the words of the Most High, "Say, 'I do not know whether what you are promised is near, or whether my Lord will grant it a long time.'" [Jinn 72:25].In another version he has from Suhayl, who said, my father sent me to Banu Haritha. He said, and with me was a boy of ours (or a companion of ours), and a caller called out to him by name from an orchard. He said, and the one who was with me looked up over the wall but saw nothing. I mentioned that to my father, and he said, "Had I known you would encounter this, I would not have sent you, but when you hear a voice, call out for prayer, for I heard Abu Hurairah relate from the Messenger of Allah ﷺ that he said, 'When the call to prayer is made, Satan turns away and breaks wind as he flees.'"Hisas means passing wind, though it has also been said that hisas means running rapidly.