Zaid b Khalid al-Juhani said:I would definitely watch at night the prayer observed by the Messenger of Allah (ﷺ). He prayed two short rak'ahs, then two long, long, long rak'ahs, then he prayed two rak'ahs which were shorter than the two preceding rak'ahs, then he prayed two rak'ahs which were shorter than the two preceding, then he prayed two rak'ahs which were shorter than the two preceding, then observed a single one (Witr), making a total of thirteen rak'ahs
وَحَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، عَنْ مَالِكِ بْنِ أَنَسٍ، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي بَكْرٍ، عَنْ أَبِيهِ، أَنَّ عَبْدَ اللَّهِ بْنَ قَيْسِ بْنِ مَخْرَمَةَ، أَخْبَرَهُ عَنْ زَيْدِ بْنِ خَالِدٍ الْجُهَنِيِّ، أَنَّهُ قَالَ لأَرْمُقَنَّ صَلاَةَ رَسُولِ اللَّهِ صلى الله عليه وسلم اللَّيْلَةَ فَصَلَّى . رَكْعَتَيْنِ خَفِيفَتَيْنِ ثُمَّ صَلَّى رَكْعَتَيْنِ طَوِيلَتَيْنِ طَوِيلَتَيْنِ طَوِيلَتَيْنِ ثُمَّ صَلَّى رَكْعَتَيْنِ وَهُمَا دُونَ اللَّتَيْنِ قَبْلَهُمَا ثُمَّ صَلَّى رَكْعَتَيْنِ وَهُمَا دُونَ اللَّتَيْنِ قَبْلَهُمَا ثُمَّ صَلَّى رَكْعَتَيْنِ وَهُمَا دُونَ اللَّتَيْنِ قَبْلَهُمَا ثُمَّ صَلَّى رَكْعَتَيْنِ وَهُمَا دُونَ اللَّتَيْنِ قَبْلَهُمَا ثُمَّ أَوْتَرَ فَذَلِكَ ثَلاَثَ عَشْرَةَ رَكْعَةً .
Muslim
The Book of Prayer - Travellers • Hadith 232