Mishkat al-Masabih 1263
Ghudaif b. al-Harith said:
I asked ‘A’isha whether she had seen God’s Messenger bathing because of sexual defilement in the early or the latter part of the night, and she replied, ‘‘He often bathed in the early part of the night and often in the latter part.” Thereupon I said, "God is most great. Praise be to God who has given latitude in the matter! ” I then asked whether he observed a witr in the early or the latter part of the night, and she replied, "He often observed it in the early part and often in the latter part of the night.” Thereupon I said, “God is most great. Praise be to God who has given latitude in the matter! ” I then asked whether he recited the Qur’an in a loud or in a low voice, and she replied, “He often recited it in a loud voice and often in a low voice.” Thereupon I said, “God is most great. Praise be to God who has given latitude in the matter!” 

Abu Dawud transmitted it, and Ibn Majah transmitted the last section.
عَن غُضَيْف بن الْحَارِث قَالَ: قُلْتُ لِعَائِشَةَ: أَرَأَيْتِ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ يَغْتَسِلُ مِنَ الْجَنَابَةِ فِي أَوَّلِ اللَّيْلِ أَمْ فِي آخِرِهِ؟ قَالَتْ: رُبَّمَا اغْتَسَلَ فِي أَوَّلِ اللَّيْلِ وَرُبَّمَا اغْتَسَلَ فِي آخِرِهِ قُلْتُ: اللَّهُ أَكْبَرُ الْحَمْدُ لِلَّهِ الَّذِي جَعَلَ فِي الْأَمْرِ سَعَةً قُلْتُ: 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 الْأَمْرِ سَعَةً قُلْتُ: كَانَ يَجْهَرُ بِالْقِرَاءَةِ أَمْ يَخْفُتُ؟ قَالَتْ: رُبَّمَا جَهَرَ بِهِ وَرُبَّمَا خَفَتَ قُلْتُ: اللَّهُ أَكْبَرُ الْحَمْدُ لِلَّهِ الَّذِي جَعَلَ فِي الْأَمْرِ سَعَةً. رَوَاهُ أَبُو دَاوُدَ وَرَوَى ابْنُ مَاجَهْ الْفَصْلَ الْأَخِيرَ