[Machine] The Messenger of Allah ﷺ used to perform voluntary prayers called "Tahajjud" with nine rak'ahs. However, as he grew older and found it burdensome, he shortened it to seven rak'ahs.
كَانَ رَسُولُ اللهِ ﷺ يُوتِرُ بِتِسْعٍ فَلَمَّا أَسَنَّ وثَقُلَ أَوْتَرَ بِسَبْعٍ
"The Messenger of Allah ﷺ used to pray nine (rak'ahs) at night, then when he grew older and put on weight he prayed seven."
كَانَ رَسُولُ اللَّهِ ﷺ يُصَلِّي مِنَ اللَّيْلِ تِسْعًا فَلَمَّا أَسَنَّ وَثَقُلَ صَلَّى سَبْعًا
"The Messenger of Allah ﷺ used to pray witr with thirteen rak'ahs, but when he grew older and weaker he prayed witr with nine." (Using translation from Nasāʾī 1727)
كَانَ رَسُولُ اللهِ ﷺ يُوتِرُ بِثَلَاثَ عَشْرَةَ فَلَمَّا كَبِرَ وَضَعُفَ أَوْتَرَ بِسَبْعٍ
[Machine] The Messenger of Allah ﷺ used to pray thirteen raka'ah in the night, but when he became old or weak, he would pray seven raka'ah.
كَانَ رَسُولُ اللهِ ﷺ «يُوتِرُ بِثَلَاثَ عَشْرَةَ فَلَمَّا كَبِرَ وَضَعُفَ أَوْتَرَ بِسَبْعٍ»
[Machine] The translation of the passage from Arabic to English is: "The Messenger of Allah ﷺ used to perform the Witr prayer with nine units, but when it became difficult for him, he would perform Witr with seven units."
«كَانَ رَسُولُ اللهِ ﷺ يُوتِرُ بِتِسْعٍ فَلَمَّا ثَقُلَ أَوْتَرَ بِسَبْعٍ»
[Machine] That the Prophet ﷺ used to perform voluntary prayers of nine units, but when he grew older and weaker, he would perform the voluntary prayers of seven units.
أَنَّ النَّبِيَّ ﷺ كَانَ «يُوتِرُ بِتِسْعٍ فَلَمَّا أَسَنَّ وَثَقُلَ أَوْتَرَ بِسَبْعٍ»