Is "holiness" a theme word today? Possibly not. The general quest is for this worldly experience and satisfaction, and "holiness" sounds as if, in some sense, it is taking a person out of the world. In fact this is how Jewish teaching explains the theme of the holy. In a famous passage in the prayer-book, the angels say "Holy, holy, holy" referring to G‑d. This is explained as meaning that however spiritual the Angels may be, G‑d is infinitely beyond and exalted, higher and higher.
Now, of course, in Jewish teaching G‑d is not only beyond the world. G‑d is also within the world. The term "Holy," however, seems to imply a step away from daily life. Is that the final word on the subject? Let us see.
The Parshah this week is called Kedoshim, which means "holy." It begins with the words: "You shall be holy, because I, G‑d, am holy."
The Sages discuss the practical implications of this statement. Rashi says it means the self restraint necessary in order to keep the rules of the Torah concerning boundaries in human relations. Ramban says it means self-restraint in general, even concerning permitted things. He quotes the Sages who tell us "Sanctify yourself in that which is permitted", meaning "restrain yourself." Just because the food is permitted, it does not mean that one has to be a glutton.
Why? Why all this self-restraint? Why not just enjoy oneself, especially if it is permitted? What is the problem?
The aim of the Torah and its teachings is not to make a person leave the world, ascending towards holiness and all that is beyond, but the reverse: to reveal holiness and G‑dliness in this physical world. Hence the many laws of the Torah which almost all concern some aspect of our physical lives. By keeping those laws we are drawing the Divine and the sacred into our physical domain, into our kitchen, office and bedroom.
However, so long that we are only keeping the minimalist aspect of the law, just that which has been specifically commanded, it is as if we are keeping the law simply because we are forced to do so. G‑d instructs us to do something, or to refrain from something, so, with a sigh, we obey. The idea of doing a little bit "extra" is in order to show that we actually identify with the quest to make our lives and our world a dwelling for G‑d. So we continue along this path, not only through the mitzvot, the sacred commandments, but also in the ordinary affairs of daily life. There too we seek to express holiness.
In this way we seek to reveal an important possibility in life: that not only the domain of the mitzvot, but every detail of existence is potentially holy. Nothing is "ordinary." The entire world is, indeed, or can become, a dwelling for G‑d.
Hence there are a number of areas of life in which we are encouraged to take an extra step, beyond the letter of the law. For example, in fulfillment of the mitzva "love your neighbor as yourself", which is also in our Parshah. Through this, so to speak, we bring holiness down to earth, reaching towards the time when "the world will be filled with knowledge of G‑d, as the waters cover the sea.
-adapted from www.chabad.org