Sunan Abi Dawud, Book 4, Hadith 1252 (USC-MSA) ⓘ

Narrated Bilal: Ziyadah al-Kindi reported on the authority of Bilal that he (Bilal) came to the Messenger of Allah to inform him about the dawn prayer. Aisha kept Bilal engaged in a matter which she asked him till the day was bright and it became fairly light. Bilal then stood up and called him to prayer and called him repeatedly. The Messenger of Allah did not yet come out. When he came out, he led the people in prayer and he (Bilal) informed him that Aisha had kept him engaged in a matter which she asked him till it became fairly light; hence he became late in reaching him (in time). He (Bilal) said: Messenger of Allah, the dawn became fairly bright. He said: If the dawn became brighter than it is now, I would pray them (the two rak'ahs of the sunnah prayer), offer them well and in a more beautiful manner.

حَدَّثَنَا أَحْمَدُ بْنُ حَنْبَلٍ، حَدَّثَنَا أَبُو الْمُغِيرَةِ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْعَلاَءِ، حَدَّثَنِي أَبُو زِيَادَةَ، عُبَيْدُ اللَّهِ بْنُ زِيَادٍ الْكِنْدِيُّ عَنْ بِلاَلٍ، أَنَّهُ حَدَّثَهُ أَنَّهُ، أَتَى رَسُولَ اللَّهِ صلى الله عليه وسلم لِيُؤْذِنَهُ بِصَلاَةِ الْغَدَاةِ فَشَغَلَتْ عَائِشَةُ - رضى الله عنها - بِلاَلاً بِأَمْرٍ سَأَلَتْهُ عَنْهُ حَتَّى فَضَحَهُ الصُّبْحُ فَأَصْبَحَ جِدًّا قَالَ فَقَامَ بِلاَلٌ فَآذَنَهُ بِالصَّلاَةِ وَتَابَعَ أَذَانَهُ فَلَمْ يَخْرُجْ رَسُولُ اللَّهِ صلى الله عليه وسلم فَلَمَّا خَرَجَ صَلَّى بِالنَّاسِ وَأَخْبَرَهُ أَنَّ عَائِشَةَ شَغَلَتْهُ بِأَمْرٍ سَأَلَتْهُ عَنْهُ حَتَّى أَصْبَحَ جِدًّا وَأَنَّهُ أَبْطَأَ عَلَيْهِ بِالْخُرُوجِ فَقَالَ ‏"‏ إِنِّي كُنْتُ رَكَعْتُ رَكْعَتَىِ الْفَجْرِ ‏"‏ ‏.‏ فَقَالَ يَا رَسُولَ اللَّهِ إِنَّكَ أَصْبَحْتَ جِدًّا ‏.‏ قَالَ ‏"‏ لَوْ أَصْبَحْتُ أَكْثَرَ مِمَّا أَصْبَحْتُ لَرَكَعْتُهُمَا وَأَحْسَنْتُهُمَا وَأَجْمَلْتُهُمَا ‏"‏ ‏.‏