And you shall inscribe them on the doorposts of your home and gates (Deuteronomy 6:9).
Some people seem to have two personalities. Some are very gentle, polite, and accommodating during the workday to clients and customers, but when they come home they become demanding and unyielding tyrants. On the other hand, others are loving, considerate, and patient at home, but in business affairs are ruthless, letting nothing stand in the way of gaining profit.
Neither behavior pattern is acceptable. Our lives must be governed by principles that apply everywhere, and we must practice them in all our affairs. For the Jew, these principles are found in the Torah, which includes not only the Scriptures, but also the Talmud and the various works compiled by Torah scholars throughout the ages.
In the portion of the Torah inscribed on the mezuzah, we read that one should converse in Torah while in the home, on the road, when one arises, and when one retires. This message is to be inscribed on the doorposts of our homes. In other words, from awakening until bedtime, both within the home and outside the home, the words of the Torah are to direct us in our actions. There can be no dichotomy.
The mezuzah is affixed to the doorpost so that it should be noticed both when we leave the house to enter the world of commerce and when we return home after the workday. While it is a beautiful custom to kiss the mezuzah as a sign of endearment, this gesture should not be perfunctory. The words of the mezuzah should influence our behavior everywhere.