I did not see the Messenger of Allah ﷺ reciting (the Qur'an) in the night prayer in a sitting position, till he grew old and then he recited (it) in a sitting position, but when thirty or forty verses were left out of the Surah, he would then stand up, recite them and then bowed.
مَا رَأَيْتُ رَسُولَ اللَّهِ ﷺ يَقْرَأُ فِي شَىْءٍ مِنْ صَلاَةِ اللَّيْلِ جَالِسًا حَتَّى إِذَا كَبِرَ قَرَأَ جَالِسًا حَتَّى إِذَا بَقِيَ عَلَيْهِ مِنَ السُّورَةِ ثَلاَثُونَ أَوْ أَرْبَعُونَ آيَةً قَامَ فَقَرَأَهُنَّ ثُمَّ رَكَعَ