Musnad Abu Ya'la al-Mawsili 42:30

'Umar ibn Shabbah narrated to us, 'Umar ibn 'Ali al-Muqaddami narrated to us, he said: I heard Talhah ibn 'Abdullah mentioning from 'Atiyyah al-'Awfi, from Abu Sa'id al-Khudri, that the Messenger of Allah (may Allah bless him and grant him peace) said: "Indeed, the highest of people in rank on the Day of Resurrection is the just leader. And indeed, the lowest of people in rank on the Day of Resurrection is the leader who is not just."