Sahih Muslim 655
Sahih Muslim · Book 5: The Book of Mosques and Places of Prayer · The prohibition of leaving the masjid once the Mu’adhdhin has called the Adhan
Abu Sha'tha' al-Muharibi reported on the authority of his father, who said:
وَحَدَّثَنَا ابْنُ أَبِي عُمَرَ الْمَكِّيُّ ، حَدَّثَنَا سُفْيَانُ، - هُوَ ابْنُ عُيَيْنَةَ - عَنْ عُمَرَ بْنِ سَعِيدٍ ، عَنْ أَشْعَثَ بْنِ أَبِي الشَّعْثَاءِ الْمُحَارِبِيِّ، عَنْ أَبِيهِ ، قَالَ سَمِعْتُ أَبَا هُرَيْرَةَ ، وَرَأَى، رَجُلاً يَجْتَازُ الْمَسْجِدَ خَارِجًا بَعْدَ الأَذَانِ فَقَالَ أَمَّا هَذَا فَقَدْ عَصَى أَبَا الْقَاسِمِ صلى الله عليه وسلم .
I heard it from Abu Huraira that he saw a person getting out of the mosque after the call to prayer had been announced. Upon this he remarked: This (man) disobeyed Abu'l-Qasim (ﷺ).