Abdullah bin al-Samit narrates that Sayyiduna Abu Dharr (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "O Abu Dharr, soon there will be rulers (imams) over you who will kill the prayer (by delaying it from its time). If you find them, pray the prayer at its proper time, and make the prayer you offer with them (again) a voluntary prayer."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1620