It was narrated from 'Awn bin Abu Juhaifah that his father said:

"I came to the Messenger of Allah in Abtah, when he was in a red tent. Bilal came out and gave the call to prayer, turning around and putting his fingers in his ears."

حَدَّثَنَا أَيُّوبُ بْنُ مُحَمَّدٍ الْهَاشِمِيُّ، حَدَّثَنَا عَبْدُ الْوَاحِدِ بْنُ زِيَادٍ، عَنْ حَجَّاجِ بْنِ أَرْطَاةَ، عَنْ عَوْنِ بْنِ أَبِي جُحَيْفَةَ، عَنْ أَبِيهِ، قَالَ أَتَيْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ بِالأَبْطَحِ وَهُوَ فِي قُبَّةٍ حَمْرَاءَ فَخَرَجَ بِلاَلٌ فَأَذَّنَ فَاسْتَدَارَ فِي أَذَانِهِ وَجَعَلَ إِصْبَعَيْهِ فِي أُذُنَيْهِ ‏.‏