Narrated Jabir bin Abdullah: While Allah's Apostle was distributing the booty at Al-Ja'rana, somebody said to him "Be just (in your distribution)." The Prophet replied, "Verily I would be miserable if I did not act justly."
— Sahih Bukhari, Volume 4, Book 53: One-fifth of Booty to the Cause of Allah (Khumus), Hadith #366