Distrust You Self!
As a youngster Saint Pambo asked Saint Antony of Egypt (his mentor) "Teach me, my Father, to live well." To which the elder Saint replied "My son, to live well, one must have a great distrust of oneself, with every effort watch over one's heart and mind, do penance, and seek God alone in all things."
In Butler's and a German devotional I am using he is the saint for 6th of September.