when the prophet ﷺ prayed sitting, he recited the Quran in sitting condition. When the amount of his recitation remained about thirty or forty verses he stood up and recited them standing. He then bowed and prostrated and then did so in the second Rak’ah of the prayer. Abu Dawud said: 'Alqamah b. Waqqas narrated this tradition on the authority of 'Aishah from the Prophet ﷺ to the same effect. (Using translation from Abū Dāʾūd 954)   

أَنَّ رَسُولَ اللهِ ﷺ كَانَ يُصَلِّي جَالِسًا فَيَقْرَأُ وَهُوَ جَالِسٌ فَإِذَا بَقِيَ مِنْ قِرَاءَتِهِ قَدْرَ مَا يَكُونُ ثَلَاثِينَ أَوْ أَرْبَعِينَ آيَةً قَامَ فَقَرَأَ وَهُوَ قَائِمٌ ثُمَّ رَكَعَ ثُمَّ سَجَدَ ثُمَّ يَفْعَلُ فِي الرَّكْعَةِ الثَّانِيَةِ مِثْلَ ذَلِكَ