Musnad Ahmad 1012:25

Ya'mar, meaning Ibn Bishr, narrated to us, Abdullah informed us, Sufyan informed us, from Mansur, from Hilal ibn Yasaf, from Abu al-Muthanna al-Homsi, from the father of Ubayy, the husband of the wife of Ubadah ibn al-Samit, who said: We were sitting with the Messenger of Allah, may Allah bless him and grant him peace, and he said: "O people, there will come rulers who will be preoccupied by things, until they do not pray the prayer at its appointed time. So, pray the prayer at its appointed time." A man said: "O Messenger of Allah, should we then pray with them?" He said: "Yes." Abdullah said: My father, may Allah have mercy on him, said: And this is the correct [version].