Quotes about honesty from throughout Christian History.
Justin Martyr, c. AD 150
He has exhorted us to lead all men, by patience and gentleness, from shame and the love of evil. And this indeed is proved in the case of many who once were of your way of thinking, but have changed their violent and tyrannical disposition, being overcome either by the constancy which they have witnessed in their neighbor's lives, or by the extraordinary forbearance they have observed in their fellow travelers when defrauded, or by the honesty of those with whom they have transacted business. (First Apology 16)
Tertullian, c. AD 210
The Christian is noted for his fidelity even among those who are not of his religion. (Apology 46)
Eusebius, AD 323
In this passage, Eusebius is quoting Justin speaking against Crescens, a philosopher trying to imitate the Cynics.
For the man is not worthy to be called a philosopher who publicly bears witness against those concerning whom he knows nothing, declaring, for the sake of captivating and pleasing the multitude, that the Christians are atheistic and impious. Doing this he errs greatly. For if he assails us without having read the teachings of Christ, he is thoroughly depraved, and is much worse than the illiterate, who often guard against discussing
and bearing false witness about matters which they do not understand. (History of the Church IV:16)