Musnad Ahmad 32:1387

Ishaq ibn Isa and Hashim narrated to us, they said: Layth narrated to us, Ibn Shihab narrated to me, from Anas ibn Malik, that he informed him: "That the Messenger of Allah, may Allah bless him and grant him peace, used to pray the Asr prayer while the sun was high and bright. So the person going to the Al-Awali would depart, and he would arrive at the Al-Awali while the sun was still high."