Nasai

´It was narrated that Abu Sa'eed Al-Khudri said:` "We used to estimate how long the Messenger of Allah (ﷺ) stood when praying in Zuhr and 'Asr. We estimated that he stood in Zuhr for as long as it take to recite thirty verses, as long as Surat As-Sajadah in the fits two Rak'ahs, and half that in the last two. And we estimated that he stood for as long in the fits two Rak'ahs, and half that in the last two. And we estimated that he stood for as long in the first two Rak'ahs of 'Asr as he stood in the last two Rak'ahs of Zuhr, and we estimated that he stood half as long as that in the last two Rak'ahs of 'Asr."

Abu Saeed Al Khudri said: We used to estimate how long the Messenger of Allah ﷺ stood in the noon and the afternoon prayer, and we estimated that he stood in the first two rak’ahs of the noon prayer as long as it takes to recite thirty verses (of the Quran), such as A-L-M Tanzil al-Sajdah. And we estimated that he stood in the last two rak’ahs half the time he stood in the first two rak’ahs. We estimated that he stood in the first two rak’ahs of the afternoon prayer as long as he did in the last two at noon; and we estimated that he stood in the last two rak’ahs of the afternoon prayer half the time he did in first two.