9 But if there be among us, most beloved brother, the fear of God, if the maintenance of the faith prevail, if we keep the precepts of Christ, if we guard the incorrupt and inviolate sanctity of His spouse, if the words of the Lord abide in our thoughts and hearts, when he says, “Do you think, when the Son of man comes, shall He find faith on the earth” then, because we are God's faithful soldiers, who war for the faith and sincere religion of God, let us keep the camp entrusted to us by God with faithful valour.
Nor ought custom, which had crept in among some, to prevent the truth from prevailing and conquering; for custom without truth is the antiquity of error. On which account, let us forsake the error and follow the truth, knowing that in Esdras also the truth conquers, as it is written: “Truth endures and grows strong to eternity, and lives and prevails for ever and ever. With her there is no accepting of persons or distinctions; but what is just she does: nor in her judgments is there unrighteousness, but the strength, and the kingdom, and the majesty, and the power of all ages.
Blessed be the Lord God of truth!” This truth Christ showed to us in His Gospel, and said, “I am the truth.” Wherefore, if we are in Christ, and have Christ in us, if we abide in the truth, and the truth abides in us, let us keep fast those things which are true.
Source: The Epistles of Cyprian (New Advent)