عَنْ أَبِي أُمَامَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يُوْتِرُ بِتِسْعٍ حَتَّى إِذَا بَدُنَ وَكَثُرَ لَحْمُهُ أَوْتَرَ بِسَبْعٍ وَصَلَّى رَكْعَتَيْنِ وَهُوَ جَالِسٌ فَقَرَأَ بِـ{إِذَا زُلْزِلَتْ} وَ{قُلْ يَا أَيُّهَا الْكَافِرُونَ}
Sayyiduna Abu Umamah narrates that the Messenger of Allah (peace and blessings be upon him) used to offer nine (9) rak‘ahs of Witr, but when he became heavy and his flesh increased, he (peace and blessings be upon him) would offer seven Witr, and after the Witr, he would sit and perform two rak‘ahs, in which he would recite Surah Az-Zalzalah and Surah Al-Kafiroon.