He used to sleep in the early part of the night, and woke up in the latter part. If he then wished intercourse with his wife, he satisfied his desire, and then went to sleep; and when the first call to prayer was made he jumped up (by Allah, she, i. e. 'A'isha, did not say" he stood up" ), and poured water over him (by Allah she, i. e. 'A'isha, did not say that he took a bath but I know what she meant) and if he did not have an intercourse, he performed ablution, just as a man performs ablution for prayer and then observed two rak'ahs.  

عَنْ صَلاَةِ رَسُولِ اللَّهِ ﷺ قَالَتْ كَانَ يَنَامُ أَوَّلَ اللَّيْلِ وَيُحْيِي آخِرَهُ ثُمَّ إِنْ كَانَتْ لَهُ حَاجَةٌ إِلَى أَهْلِهِ قَضَى حَاجَتَهُ ثُمَّ يَنَامُ فَإِذَا كَانَ عِنْدَ النِّدَاءِ الأَوَّلِ قَالَتْ وَثَبَ وَلاَ وَاللَّهِ مَا قَالَتْ قَامَ فَأَفَاضَ عَلَيْهِ الْمَاءَ وَلاَ وَاللَّهِ مَا قَالَتِ اغْتَسَلَ وَأَنَا أَعْلَمُ مَا تُرِيدُ وَإِنْ لَمْ يَكُنْ جُنُبًا تَوَضَّأَ وُضُوءَ الرَّجُلِ لِلصَّلاَةِ ثُمَّ صَلَّى الرَّكْعَتَيْنِ  

"I asked 'Aishah about the prayer of the Messenger of Allah ﷺ. She said: 'He used to sleep during the first part of the night, then get up during the time before dawn and pray witr. Then he would go to his bed and if he needed to be intimate he would go to his wife. Then when he heard the Adhan he would get up, and if he was junub he would pour water over himself, otherwise he would perform wudu, then he would go out to the prayer.'" (Using translation from Nasāʾī 1680)  

عَنْ صَلَاةِ رَسُولِ اللهِ ﷺ بِاللَّيْلِ فَقَالَتْ كَانَ يَنَامُ أَوَّلَ اللَّيْلِ ثُمَّ يَقُومُ فَإِذَا كَانَ مِنَ السَّحَرِ أَوْتَرَ ثُمَّ أَتَى فِرَاشَهُ فَإِنْ كَانَتْ لَهُ حَاجَةٌ أَلَمَّ بِأَهْلِهِ فَإِذَا سَمِعَ الْأَذَانَ وَثَبَ فَإِنْ كَانَ جُنُبًا أَفَاضَ عَلَيْهِ الْمَاءَ وَإِلَّا تَوَضَّأَ ثُمَّ خَرَجَ إِلَى الصَّلَاةِ  

He used to sleep in the early part of the night, and woke up in the latter part. If he then wished intercourse with his wife, he satisfied his desire, and then went to sleep; and when the first call to prayer was made he jumped up (by Allah, she, i. e. 'A'isha, did not say" he stood up" ), and poured water over him (by Allah she, i. e. 'A'isha, did not say that he took a bath but I know what she meant) and if he did not have an intercourse, he performed ablution, just as a man performs ablution for prayer and then observed two rak'ahs. (Using translation from Muslim 739)  

عَنْ صَلَاةِ رَسُولِ اللهِ ﷺ قَالَتْ كَانَ يَنَامُ أَوَّلَ اللَّيْلِ وَيُحْيِي آخِرَهُ ثُمَّ إِنْ كَانَتْ لَهُ حَاجَةٌ إِلَى أَهْلِهِ قَضَى حَاجَتَهُ ثُمَّ نَامَ قَبْلَ أَنْ يَمَسَّ مَاءً فَإِذَا كَانَ عِنْدَ النِّدَاءِ الْأَوَّلِ قَالَتْ وَثَبَ وَلَا وَاللهِ مَا قَالَتْ قَامَ فَأَفَاضَ عَلَيْهِ الْمَاءَ وَلَا وَاللهِ مَا قَالَتْ اغْتَسَلَ وَأَنَا أَعْلَمُ بِمَاتُرِيدُ وَإِنْ لَمْ يَكُنْ جُنُبًا تَوَضَّأَ وُضُوءَ الرَّجُلِ لِلصَّلَاةِ ثُمَّ صَلَّى الرَّكْعَتَيْنِ  

[Machine] About the night prayer of the Prophet ﷺ , it was said, "He used to sleep at the beginning of the night and then get up to pray. When it was close to dawn, if he had a need for his family, he would go to them, otherwise he would sleep. When he heard the call to prayer, he would quickly get up and what she (referring to the narrator) did not say was that he would perform a ritual bath if he was in a state of major ritual impurity, otherwise he would perform ablution. Then he would go out to pray."  

عَنْ صَلَاةِ النَّبِيِّ ﷺ بِاللَّيْلِ فَقَالَتْ «كَانَ يَنَامُ أَوَّلَ اللَّيْلِ ثُمَّ يَقُومُ فَيُصَلِّي فَإِذَا كَانَ مِنَ السَّحَرِ أَوْتَرَ فَإِنْ كَانَتْ لَهُ حَاجَةٌ إِلَى أَهْلِهِ وَإِلَّا نَامَ فَإِذَا سَمِعَ الْأَذَانَ وَثَبَ وَمَا قَالَتْ قَامَ فَإِنْ كَانَ جُنُبًا أَفَاضَ عَلَيْهِ مِنَ الْمَاءِ وَمَا قَالَتِ اغْتَسَلَ وَإِلَّا تَوَضَّأَ وَخَرَجَ إِلَى الصَّلَاةِ»  

"عَنْ الأَسْوَدِ بْنِ يَزِيدَ قَالَ: سَأَلْتُ عَائِشَةَ عَنْ صَلاةِ رَسُولِ اللهِ ﷺ فَقَالَتْ: كَانَ يَنَامُ أَوَّلَ اللَّيْلِ وَيَقُومُ آخِرَهُ، فُيَصَلِّي مَا قُضِيَ لَهُ، فَإِذَا قَضَى صَلَاتَهُ مَالَ إِلَى فِرَاشِهِ، فَإِنْ كَانَتْ لَهُ حَاجَةٌ إِلَى أَهْلِهِ أَتَى أَهْلَهُ، ثُمَّ يَنَامُ كَهَيْئَتِهِ لَمْ يَمَسَّ مَاءً، فَإِذَا سَمِعَ المُنَادِىَ الأَوَّلَ قَامَ، فَإِنْ كَانَ جُنُبًا اغْتَسَلَ، وَإِنْ لَمْ يَكُنْ جُنُبًا تَوَضَّأَ وُضُوءَهُ للِصَّلَاةِ، ثم صلى ركعتين ثُمَّ خَرَجَ إِلَى الصَّلَاةِ".