Rabbeinu Bechayei explains that the expression "righteous" best portrays a man who takes extreme precautions in matters related to theft and "upright" distinguishes a man who acts with integrity.

To help us understand what integrity means, let us recount the following true story:

A wealthy widow died young, leaving behind a considerable legacy. Before dying, she summoned her daughter who was old enough to marry and said to her: "I will leave all my possessions to you as an inheritance, on the condition that you go to a specific yeshiva and ask the Rosh Yeshiva to set you up to marry his best yeshiva student. The girl followed her mother's instructions and met the Rosh Yeshiva who advised her to marry Reuben, the yeshiva’s most prominent student. The young woman met Reuben twice and without giving the matter too much thought, decided to marry him.

A few days later, before the wedding celebration’s due date, the girl heard that Reuben was not the best student in the Yeshiva; the best student was Shimon. Obviously perturbed that if she married Reuben, she would go against her mother's wishes, the girl did not know what to do, despite the Rosh Yeshiva recommendation. She was so obviously distraught that Reuben asked for an explanation. She then explained the situation. Since Reuben was a righteous man, who was very rigorous concerning theft, and wanted to avoid taking advantage of a situation for which he seemed unfit, he said to his fiancée: "I understand your embarrassment, and you are right; it is possible that if you marry me, you will not fulfill your mother's wishes. To this end, I'm backing off and setting you free to marry whoever you like. I forgive you and you have absolutely no need to apologize. "

The two parted. Nevertheless, the girl asked Reuben to write to her a waiver of forgiveness. Soon enough, she was engaged and married Shimon. Some months went by up until one fine day, an important Rosh Yeshiva appeared at Reuben and Shimon’s yeshiva. He asked the Rosh Yeshiva to introduce him to a talented student who could serve as Rav in his Yeshiva. Without hesitation, the Rav introduced Reuben. He was summoned and offered the distinguished position, but he refused, much to the surprise of both Rabbis. Any other student would have been flattered by an offer of that caliber. No matter how much they tried to persuade him to accept the appointment and how much they claimed he could spread the Torah among the Jewish people, the latter declined.

The Rosh Yeshiva departed. The Rav and Reuben were left alone. Reuben explained: "I know that many people would dream to lead this Yeshiva but ... how can I accept this appointment? If the girl with whom I was supposed to get married is informed that I have been hired to take this position, she might feel she made a bad choice and married the wrong husband; and that will cause her great distress. I prefer to decline this post to avoid hurting an orphan. By definition, Reuben's behavior is the ultimate example of righteousness and integrity!