Amr bin Maymun al-Awdi says: Mu'adh bin Jabal (may Allah be pleased with him) came to Yemen as the envoy of the Prophet (peace and blessings be upon him). I heard his takbir in the Fajr prayer; he was a man with a deep, husky voice. Love for him settled in my heart, and I did not part from him until I buried him in Syria. After him I found Ibn Mas'ud (may Allah be pleased with him) to be the most learned of all people in religion, so I came to him and stayed with him until he passed away. He said: The Messenger of Allah (peace and blessings be upon him) said: "What will you do when rulers pray the prayers after delaying them from their times?" I said: "What do you (peace and blessings be upon him) command me if I live to see that time?" He (peace and blessings be upon him) said: "Pray the prayer at its time, and make your prayer with them voluntary."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5316