Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with the same chain of narration, it is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When the call to prayer (adhan) is given, Satan flees while passing wind so that he does not hear the adhan. Then when the adhan is completed, he returns. Likewise, when the iqamah for prayer is pronounced, he turns his back and flees. Then when the iqamah is completed, he comes back until he casts whispers between a person and his heart. He says, 'Remember such and such thing,' which he had not remembered before, until (because of these whispers) a person does not know how much he has prayed."