It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "After me there will be rulers who will not offer the prayer at its proper time. When they do that, offer the prayer at its time, and make the prayer you offer with them a voluntary (nafl) prayer."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Ziyad bin Abi Ziyad except Dawud bin Bakr, and Umar bin Hafs bin Dhakwan is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الميم / 8845
Hadith Takhrij«أخرجه الضياء المقدسي فى «الأحاديث المختارة» برقم: 2143، وأبو يعلى فى «مسنده» برقم: 4323، وابن حجر فى «المطالب العالية» برقم: 274»