حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا الْمُعْتَمِرُ، ح حَدَّثَنَا أَحْمَدُ بْنُ حَنْبَلٍ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ، قَالاَ حَدَّثَنَا بُرْدُ بْنُ سِنَانٍ، عَنْ عُبَادَةَ بْنِ نُسَىٍّ، عَنْ غُضَيْفِ بْنِ الْحَارِثِ، قَالَ قُلْتُ لِعَائِشَةَ أَرَأَيْتِ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَغْتَسِلُ مِنَ الْجَنَابَةِ فِي أَوَّلِ اللَّيْلِ أَوْ فِي آخِرِهِ قَالَتْ رُبَّمَا اغْتَسَلَ فِي أَوَّلِ اللَّيْلِ وَرُبَّمَا اغْتَسَلَ فِي آخِرِهِ ‏.‏ قُلْتُ اللَّهُ أَكْبَرُ الْحَمْدُ لِلَّهِ الَّذِي جَعَلَ فِي الأَمْرِ سَعَةً ‏.‏ قُلْتُ أَرَأَيْتِ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُوتِرُ أَوَّلَ اللَّيْلِ أَمْ فِي آخِرِهِ قَالَتْ رُبَّمَا أَوْتَرَ فِي أَوَّلِ اللَّيْلِ وَرُبَّمَا أَوْتَرَ فِي آخِرِهِ ‏.‏ قُلْتُ اللَّهُ أَكْبَرُ الْحَمْدُ لِلَّهِ الَّذِي جَعَلَ فِي الأَمْرِ سَعَةً ‏.‏ قُلْتُ أَرَأَيْتِ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَجْهَرُ بِالْقُرْآنِ أَمْ يَخْفِتُ بِهِ قَالَتْ رُبَّمَا جَهَرَ بِهِ وَرُبَّمَا خَفَتَ ‏.‏ قُلْتُ اللَّهُ أَكْبَرُ الْحَمْدُ لِلَّهِ الَّذِي جَعَلَ فِي الأَمْرِ سَعَةً ‏.‏

Narrated Aisha, Ummul Mu'minin: Ghudayf ibn al-Harith reported: I asked Aisha: Have you seen the Messenger of Allah (PBUH) washing (because of defilement) at the beginning of the night or at the end? She replied: Sometimes he would take a bath at the beginning of the night and sometimes at the end. Thereupon I exclaimed: Allah is most Great. All Praise be to Allah Who made this matter accommodative. I again asked her: What do you think, did the Messenger of Allah (PBUH) say the witr prayer (additional prayer after obligatory prayer at night) in the beginning of the night or at the end? She replied: Sometimes he would say the witr prayer at the beginning of the night and sometimes at the end. I exclaimed: Allah is most Great. All praise be to Allah Who made the matter accommodative. Again I asked her: What do you think, did the Messenger of Allah (PBUH) recite the Qur'an (in the prayer) loudly or softly? She replied: Sometimes he would recite loudly and sometimes softly. I exclaimed: Allah is most Great. All praise be to Allah Who made the matter flexible. Translation Not Available

Book Ref: Sunan Abi Dawud Book 1 Hadith 226
Web Ref:  Sunan Abi Dawud Book 1 Hadith 226