Musnad Ahmad 28:515

Yahya ibn Abi Bukayr narrated to us, Shu'bah narrated to us, from Qatadah, who said: I heard Abu Ayyub al-Azdi narrating from Abdullah ibn Amr, who said—he did not attribute it to the Prophet twice, then I asked him a third time, and he said—the Messenger of Allah (peace and blessings of Allah be upon him) said: "The time for the Dhuhr prayer is as long as the Asr has not arrived. The time for the Asr prayer is as long as the sun has not turned yellow. The time for the Maghrib prayer is as long as the light of the twilight has not fallen. The time for the Isha prayer is until the middle of the night. And the time for the Fajr prayer is as long as the sun has not risen."