Musnad Ahmad 534:8

Abu al-Mughirah narrated to us, Safwan narrated to us, Azhar ibn Abdullah narrated to us, from Abdullah ibn Busr, who said: "I heard a hadith a long time ago: If you are among a people of twenty men, or fewer, or more, and you examine their faces, and you do not see among them a man who is feared for the sake of Allah, then know that the matter has become thin."