Before we can grasp the significance of kosher, we need to understand the Jewish approach to eating and life itself. Put simply, we are here to transform the physical realm into a place that G-d can call home. Of course, a home must be consistent with the will and design concept of its inhabitant. So, in making the world G-d's home we are His interior designers. Every aspect of our life is an element in the Divine abode.
Now don't get discouraged. This is possible and you do it much more often than you may be aware. (You may be doing it this very moment.) The idea is that our general theme in life is to serve G-d. Staying healthy, supporting our families and relaxing are all important components to this service. They can all be seen within the context of transforming the world. Let's take eating for example. First, one aspect of serving G-d is being healthy and strong; and eating is part of this service. As Maimonides puts it "...keeping the body healthy is part of serving G-d."
Second, we are endowed with the ability to actually elevate the food by eating it with the proper intention. Let's take a look at an apple. A G-dly spark was invested in the apple. That spark was its 'soul' or vitality. The spark, however, was entrapped in the physical form of the apple. When one eats the apple within the life context of serving G-d, the spark is released from its physical trappings. It unites with the person's intention to serve G-d, and becomes a revealed part of G-dliness. When this spiritual energy in the food is realized it also adds to the eater's spiritual awareness.
So, eating is not just a matter of pleasing our palate. It isn't even a matter of keeping ourselves alive. It is a spiritual service that requires focus and direction.
A story is related about a half cup of water, the other half of which had been consumed by a human being. One half of the cup was jealous of the other, but which half of which? It depends on whether the person had the proper intentions when drinking it.
Every aspect of creation becomes incorporated into the level above it. Minerals and water sustain plants. Plants sustain animals. All three levels sustain man. Although man's soul ascends to heaven, his body returns to dust. If man does nothing with his existence, he brings all of creation back to dust, the lowest level. Conversely, man has the ability to elevate his sustenance to a level of Divinity.
Now that we understand what eating is about, we can understand why certain foods are forbidden.
Bound and Unbound
Jewish mysticism explains a reality called 'Klipah' or 'husk'. This husk conceals the G-dly spark that gives life to every creature. The husk renders the spark inaccessible. This is what we call evil. The inherent G-dliness is trapped in the vestments of the klipah and is unable to express itself and rise to a higher level.
The Hebrew word for forbidden is 'Asur' which literally means bound up. The energy or soul of food that is not kosher is bound to the husks and cannot be elevated. Since the point of eating is to elevate the food, and non-kosher food cannot be elevated, it is forbidden to eat it.
Certainly, non-kosher foods have a G-dly spark in them as well. Indeed, their energy is metabolized. However, since the G-dly spark is bound up with the husk, it cannot be elevated through ingestion. This spark remains trapped in the physical without the possibility of ascent. (There are other ways to elevate a non-kosher animal, such as riding on it. In the latter case, the undesirable energy does not enter the body.)
In contrast, 'Mutar', the Hebrew word for permissible, literally means unbound. The energy of permissible foods is not bound to the klipah and thus can be elevated through having the proper intentions and using the energy for a G-dly purpose.
Eating non-kosher food results in another problem. The unprocessed spark in the non-kosher food acts like any foreign element in the body. Energy was meant to be metabolized, and this applies to spiritual energy as well. Since the spark cannot be processed by elevation, it causes a spiritual blockage that retards our ability to relate to holiness.
Certainly, one can become accustomed to a low level of sensitivity. But, for example, if we eat only healthy food, we will feel the effect of a small measure of unhealthy food. This reaction does not mean that we are unhealthy, but on the contrary, that we have a heightened sensitivity. Similarly, through eating non-kosher food, we build a level of tolerance to it. But if we alter our diet to kosher food, the sensitivity slowly returns.
The Torah says, at the end of the laws of kashrut, 'And you shall sanctify yourselves and you shall be holy.' Through keeping kosher we attain a level of sanctity. What is this sanctity about?
In Hebrew the word for holy is 'Kadosh' which connotes being removed or separated. Being holy means being a little separated from the mundane world. It means breaking free of the cycle of eating, sleeping, working, etc. Rather, one has a higher aspiration: the pursuit of G-dliness. We remember this every time we eat. We cannot eat whatever our heart desires, because we are beyond this level of existence. Our eating is for a specific purpose and we thus ingest a specific diet.
Often we may look at eating as an end in itself. This is not holy; it is a shallow approach. The concept of holiness through kashrut is that eating becomes a means to an end. We are not connected to the mundane, we are only utilizing it. Then, things of the world are not mundane at all, but rather a part of spiritual growth.
One of the beauties of kashrut is that it is constant. Unlike Shabbos or holidays or family purity, its disciplines are relevant every day, and we are able to infuse our day and atmosphere with holiness every time we shop, every time we eat.
Although we may have some notion of why we keep kosher, ultimately its reason is still beyond us. It belongs to a category of Mitzvot called 'Chukim'.
The first category of Mitzvot is 'Mishpatim'. Mishpatim are logical laws that we would think of on our own even if G-d had not commanded them.
The second is 'Eidut'. We would not think of these had they not been commanded, but now that they have been commanded we understand their significance. One example is Shabbat. We would not have kept Shabbat on our own, but now that Hashem has commanded it, we understand that it was given as a remembrance of creation.
The third category is Chukim. Even after they were commanded, we really cannot understand them. Kashrut is such a set of laws. What does it represent? We do not know.
Keeping the Chukim is a special part of our relationship with Hashem. If we know the reason for something, then we are doing the act because of our understanding, not because of G-d's will. Ultimately, we cannot connect with Him in this situation because we are moved not by Him, but rather by our understanding. This is not a true relationship.
By way of example, if a wife makes a request and the husband responds that he will do it only if she explains it to him, the relationship is deficient. There is something special and intimate about doing something just because your spouse requested it. This request and the subsequent fulfilling of the request, without reason, reflects a deep harmony between the husband and wife.
When we do an act, or refrain from doing an act, because it is G-d's will, we are able to connect with Him in a special and intimate way. His will becomes the drive behind our action, not our own will and understanding. When we connect with G-d only because we understand, then we are connecting with our understanding. This is a shallow, if not strained, relationship. So, kashrut gives us an opportunity to connect with G-d in our every day life. Every time we eat we can be cognizant of fulfilling G-d's will through our eating.
There are many good reasons to keep Kosher, some mentioned here and even more in other works. Ultimately, though, it is a plan designed by G-d for the Jewish body. And it works.
If you're thinking of making your home Kosher, you needn't start with the entire plan. Call a Rabbi or friend who can help you in making a very meaningful decision in your life.