Narrated Aisha, Ummul Mu'minin:

Sa'd ibn Hisham said: I came to Medina and called upon Aisha, and said to her: Tell me about the prayer of the Messenger of Allah ﷺ.

She said: The Messenger of Allah ﷺ used to lead the people in the night prayer, and then go to his bed and sleep. When midnight came he got up, went to answer the call of nature and to perform ablution with water. Having performed ablution, he entered the mosque and prayed eight rak'ahs.

To my mind he performed the recitation of the Qur'an, bowing and prostrating equally. He then observed witr with one rak'ah and prayed two rak'ahs sitting. Then he lay down on the ground. Sometimes Bilal came to him and called him for prayer. He then dozed, and sometimes I doubted whether he dozed or not, till he (Bilal) called him for prayer.

This is the prayer he offered till he grew old or put on weight. She then mentioned how he put on weight as Allah wished.

حَدَّثَنَا ابْنُ الْمُثَنَّى، حَدَّثَنَا عَبْدُ الأَعْلَى، حَدَّثَنَا هِشَامٌ، عَنِ الْحَسَنِ، عَنْ سَعْدِ بْنِ هِشَامٍ، قَالَ : قَدِمْتُ الْمَدِينَةَ فَدَخَلْتُ عَلَى عَائِشَةَ فَقُلْتُ : أَخْبِرِينِي عَنْ صَلاَةِ رَسُولِ اللَّهِ ﷺ . قَالَتْ : إِنَّ رَسُولَ اللَّهِ ﷺ كَانَ يُصَلِّي بِالنَّاسِ صَلاَةَ الْعِشَاءِ، ثُمَّ يَأْوِي إِلَى فِرَاشِهِ فَيَنَامُ، فَإِذَا كَانَ جَوْفُ اللَّيْلِ قَامَ إِلَى حَاجَتِهِ وَإِلَى طَهُورِهِ فَتَوَضَّأَ، ثُمَّ دَخَلَ الْمَسْجِدَ فَصَلَّى ثَمَانِ رَكَعَاتٍ يُخَيَّلُ إِلَىَّ أَنَّهُ يُسَوِّي بَيْنَهُنَّ فِي الْقِرَاءَةِ وَالرُّكُوعِ وَالسُّجُودِ، ثُمَّ يُوتِرُ بِرَكْعَةٍ، ثُمَّ يُصَلِّي رَكْعَتَيْنِ وَهُوَ جَالِسٌ، ثُمَّ يَضَعُ جَنْبَهُ، فَرُبَّمَا جَاءَ بِلاَلٌ فَآذَنَهُ بِالصَّلاَةِ، ثُمَّ يُغْفِي، وَرُبَّمَا شَكَكْتُ أَغَفَى أَوْ لاَ، حَتَّى يُؤْذِنَهُ بِالصَّلاَةِ، فَكَانَتْ تِلْكَ صَلاَتَهُ حَتَّى أَسَنَّ وَلَحُمَ، فَذَكَرَتْ مِنْ لَحْمِهِ مَا شَاءَ اللَّهُ، وَسَاقَ الْحَدِيثَ .