Musnad Abi Ya'la 4004 — I said to Sayyiduna Anas: Tell me

Bayan (may Allah have mercy on him) narrates: I said to Sayyiduna Anas (may Allah be pleased with him): Tell me about the times of the prayers of the Messenger of Allah (peace and blessings be upon him). He said: "He (peace and blessings be upon him) used to offer the Zuhr prayer when the sun had passed its zenith, and he would pray Asr in the time between this first prayer of yours and Asr, and he used to offer the Maghrib prayer at sunset, and he would pray Isha when the twilight had disappeared, while he offered the morning prayer at dawn, when the eyesight opened (i.e. things became visible); and all the time between these is (prayer) time," or he said: "(all of it) is prayer."