Musnad Ahmad 3:16

Muhammad ibn Ja'far and Hajjaj narrated to us, they said: Shu'bah narrated to us, from 'Amr ibn Dinar, he said: I heard a man narrating from 'Uthman ibn 'Affan, from the Prophet, peace and blessings of Allah be upon him, who said: "There was a man who was easy-going when selling and when buying, and when judging and when seeking judgment, so he entered Paradise."