At work or in the army, it is important for an observant Jew to wear something which shows that he is meticulous about fulfilling the commandments and that he is not ashamed to perform them in the presence of people who are liable to make fun of him.
The Sages of the Mishna teach: "Captives should not be ransomed for more than their value, for the sake of the general welfare." The enactment of such a law was necessary in order to keep kidnapping from becoming a lucrative trade.