Musannaf Ibn Abi Shayba 21:520

Yazid ibn Harun narrated to us, from al-Asbagh ibn Yazid, from al-Qasim ibn Abi Ayyub, from Sa’id ibn Jubayr: That he used to stand upon al-Safa and al-Marwah for the duration of the recitation of a surah of the Prophet, may Allah bless him and grant him peace.