Hasan al-Basri (may Allah have mercy on him) says concerning the saying of Allah Almighty "And establish prayer at the two ends of the day" [Surah Hud: 114]: It means the Fajr prayer, and the other end means Zuhr and Asr; and "and in the early hours of the night" [Surah Hud: 114] means Maghrib and Isha.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1686