حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ عَنْ سُلَيْمَانَ عَنْ أَبِي عُثْمَانَ عَنِ ابْنِ مَسْعُودٍ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ لَا يَمْنَعَنَّ أَحَدَكُمْ أَذَانُ بِلَالٍ مِنْ سَحُورِهِ فَإِنَّهُ إِنَّمَا يُنَادِي أَوْ قَالَ يُؤَذِّنُ لِيَرْجِعَ قَائِمُكُمْ وَيُنَبِّهَ نَائِمَكُمْ لَيْسَ أَنْ يَقُولَ هَكَذَا وَلَكِنْ حَتَّى يَقُولَ هَكَذَا وَضَمَّ ابْنُ أَبِي عَدِيٍّ أَبُو عَمْرٍو أَصَابِعَهُ وَصَوَّبَهَا وَفَتَحَ مَا بَيْنَ أُصْبُعَيْهِ السَّبَّابَتَيْنِ يَعْنِي الْفَجْرَ
مسند امام احمد بن حنبل · Hadith 3717
It was narrated from Ibn Mas'ood (RA) that the Messenger of Allah (PBUH) said: "None of you should let the adhan of Bilal keep him from his sahoor, because he gives the adhan so that those of you who are praying qiyam may go back (to rest), and those of you who are asleep may wake up. It is not when it is like this; rather it is until it is like this" - and Ibn Abi 'Adiyy Abu 'Amr put his fingers together and held them pointing down (to indicate vertical) -and he spread his forefingers apart (to indicate horizontal), i.e. the dawn.
Sanad
حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ عَنْ سُلَيْمَانَ عَنْ أَبِي عُثْمَانَ عَنِ ابْنِ مَسْعُودٍ