Musnad Ahmad 28:486

'Abd al-Samad narrated to us, Hammam narrated to us, Qatadah narrated to us, from al-Hasan, from 'Abdullah ibn 'Amr, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The Hour will not be established until Allah takes His chosen ones from the people of the earth. Then there will remain in it the dregs (the base/ignorant ones), who do not recognize any good, nor do they denounce any evil."