Musnad Abu Ya'la al-Mawsili 109:157

Zuhayr narrated to us, Abd al-Rahman narrated to us, Sufyan narrated to us, from Abdullah ibn Muhammad ibn Aqil, who said: I heard Jabir saying: The Dhuhr (noon prayer) is as its name implies, and the Asr (afternoon prayer) is while the sun is alive and white, and the Maghrib (sunset prayer) is as its name implies. The Prophet, may Allah bless him and grant him peace, used to pray with us while we could see the landing spots of arrows. And the Prophet, may Allah bless him and grant him peace, used to hasten the Isha (night prayer), and the Fajr (dawn prayer) is as its name implies.