Mukhtasar Bukhari

Narrated Jabir bin Abdullah (may Allah be pleased with him): The Prophet (peace and blessings of Allah be upon him) used to offer the Zuhr prayer exactly at midday, and the Asr prayer at a time when the sun was still bright and shining, and the Maghrib prayer when the sun had set, and the Isha prayer sometimes at one time, sometimes at another. When he (peace be upon him) saw that the people had gathered, he would offer it early, and when he saw that the people were late, he would delay it. And the Fajr prayer, those people—or he said: the Prophet (peace and blessings of Allah be upon him)—used to offer in darkness.