That we must boast in nothing, since nothing is our own
In the Gospel according to John: “No one can receive anything, except it were given him from heaven.” Also in the first Epistle of Paul to the Corinthians: “For what have you that you have not received? But if you have received it, why do you boast, as if you had not received it?” Also in the first of Kings: “Boast not, neither speak lofty things, and let not great speeches proceed out of your mouth, for the Lord is a God of knowledge.” Also in the same place: “The bow of the mighty men has been made weak, and the weak are girt about with strength.” Of this same thing in the Maccabees: “It is just to be subjected to God, and that a mortal should not think things equal to God.” Also in the same place: “And fear not the words of a man that is a sinner, because his glory shall be filth and worms. Today he shall be lifted up, and tomorrow he shall not be found; because he is turned into his earth, and his thought has perished.”
Source: The Treatises of Cyprian (New Advent)