Musnad Abu Ya'la al-Mawsili 153:31

Abu Khaythama narrated to us, Yazid bin Harun narrated to us, Ibn Abi Dhi'b informed us, from al-Harith bin 'Abd al-Rahman, from Salim bin 'Abd Allah, from Ibn 'Umar, who said: The Messenger of Allah (may Allah bless him and grant him peace) used to command us to be brief, and he used to lead us in prayer with [Surah] al-Saffat during the dawn prayer.