Pride

Pride is a denial of God, an invention of the devil, contempt for men. It is the mother of condemnation, the offspring of praise, a sign of barrenness. It is a flight from God's help, the harbinger of madness, the author of downfall. It is the cause of diabolical possession, the source of anger, the gateway of hypocrisy. It is the fortress of demons, the custodian of sins, the source of hardheartedness. It is the denial of compassion, a bitter pharisee, a cruel judge. It is the foe of God. It is the root of blasphemy.

John Climacus (7th century monk)
quoted in The Cloister Walk