Shaytan runs from the Azan

When the Azan is called, Shaytan flees so as not to hear it.

Narrated by Abu Hurairah

When the call to prayer is made, Shaytan turns his back and flees, breaking wind so that he does not hear the call. When the call is finished he comes back, and when the iqamah is called he turns away again ...

Sahih al-Bukhari 608, Sahih Muslim 389

What this hadith teaches

The words of the Azan drive Shaytan away. This is why scholars encourage calling the Azan, even when alone in the countryside.

Reference and grade

Grade
Sahih: agreed upon by al-Bukhari and Muslim
Narrator
Abu Hurairah

The hadith in Arabic نص الحديث

إِذَا نُودِيَ لِلصَّلاَةِ أَدْبَرَ الشَّيْطَانُ وَلَهُ ضُرَاطٌ حَتَّى لاَ يَسْمَعَ التَّأْذِينَ، فَإِذَا قَضَى النِّدَاءَ أَقْبَلَ، حَتَّى إِذَا ثُوِّبَ بِالصَّلاَةِ أَدْبَرَ، حَتَّى إِذَا قَضَى التَّثْوِيبَ أَقْبَلَ حَتَّى يَخْطُرَ بَيْنَ الْمَرْءِ وَنَفْسِهِ، يَقُولُ اذْكُرْ كَذَا، اذْكُرْ كَذَا‏.‏ لِمَا لَمْ يَكُنْ يَذْكُرُ، حَتَّى يَظَلَّ الرَّجُلُ لاَ يَدْرِي كَمْ صَلَّى

Arabic text of Sahih al-Bukhari 608, as given on sunnah.com.