سنن أبي داود

Abu sa’id 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 Qur’an), 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.