وَعَنْ اِبْنِ عُمَرَ;
«إِنَّ بِلَالاً أَذَّنَ قَبْلَ اَلْفَجْرِ، فَأَمَرَهُ اَلنَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: أَنْ يَرْجِعَ، فَيُنَادِيَ: «أَلَا إِنَّ اَلْعَبْدَ نَامَ»
Bilal called for prayer before dawn and the Prophet (sallallahu alayhi wa sallam) told him to return and announce: “Lo! the slave of Allah (i.e. Bilal) had slept (hence this mistake)”.