Imam Bukhari narrates: Muhammad bin Yusuf narrated to us, he said: Sufyan narrated to us from Aun bin Abi Juhaifah from his own father,
he saw Bilal, may Allāh be pleased with him, giving the Adhan, so I (also) turn my face here and there (right and left) in the Adhan, following Bilal.
حَدَّثَنَا مُحَمَّدُ بْنُ يُوسُفَ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَوْنِ بْنِ أَبِي جُحَيْفَةَ، عَنْ أَبِيهِ، أَنَّهُ رَأَى بِلاَلاً يُؤَذِّنُ فَجَعَلْتُ أَتَتَبَّعُ فَاهُ هَا هُنَا وَهَا هُنَا بِالأَذَانِ.
Reference: Sahih Al Bukhari 634