Sayyiduna Anas bin Malik (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "When the evening meal has been set out and the time of prayer has come, eat before the Maghrib prayer."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5033