The real test of integrity takes place when someone is faced between keeping his word and suffering a financial loss. King David expressed this idea in Tehillim: nishba lehara' velo yamir... The honest man would keep his promise even at the cost of losing his money. Illustration: Mr. A promised to sell an item to Mr. B for 100 dollars. But later on Mr. C offers Mr. A 150 dollars for that item... If Mr. A follows King David's instruction, he will sell the item to Mr. B for 100, despite the potential monetary loss, because he already gave Mr. B his word.
The Talmud brings the ultimate example of integrity:
"Rab Safra had a donkey for sale. A gentile came to his house and offered him 50 coins for the donkey. At that precise moment Rab Safra was reciting the Shema Israel, so he could not answer back, but, the Talmud asserts that in his heart Rab Safra accepted the offer of 50 coins. The buyer, however, thought that Rab Safra's silence meant that he expected a higher price so he offered him 60 coins. Rab Safra was still reciting the Shema, so he did not react. The buyer then offered him 70 coins. At that point Rab Safra ended the Shema and he refused to accept the 70 coins. He said that in is heart he had accepted the first offer, 50 coins, and he would not take extra money from the buyer." Rab Safra was considered by the Talmud the epitome of yr-e shamayim, a man with a highest level of respect and reverence to God (Makot 24a, Rashi)
"Integrity includes but goes beyond honesty. Honesty is... conforming our words to reality. Integrity is conforming reality to our words - in other words, keeping promises and fulfilling expectations. This requires an integrated character, a oneness, primarily with self but also with life." (Stephen Covey, The 7 Habits of Highly Effective People)