Sunan Abu Dawud
1446
Sahih+3

Narrated Someone who prayed with the Prophet: Muhammad ibn Sirin said: Someone who prayed the morning prayer along with the Prophet (ﷺ) narrated to me: When he raised his head after the second rak'ah, he remained standing for a short while

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid