Why keep kosher?
Keeping kosher is one of those laws that doesn't have an obvious reason given for it in the Torah. The Torah says "Don't kill" "Don't steal" and "Honor your father and your mother" - I think it's pretty obvious what the thinking behind those commandments are. But why would G-d care if I eat shrimp or not? The following from
jewfaq.org, which has a good and thorough article on the subject, has this to say on the rationale behined the laws:
The short answer to why Jews observe these laws is: because the Torah says so. The Torah does not specify any reason for these laws, and for a Torah-observant, traditional Jew, there is no need for any other reason. Some have suggested that the laws of kashrut fall into the category of "chukkim," laws for which there is no reason. We show our obedience to G-d by following these laws even though we do not know the reason. Others, however, have tried to ascertain G-d's reason for imposing these laws.
In his book "To Be a Jew" (an excellent resource on traditional Judaism), Rabbi Hayim Halevy Donin suggests that the dietary laws are designed as a call to holiness. The ability to distinguish between right and wrong, good and evil, pure and defiled, the sacred and the profane, is very important in Judaism. Imposing rules on what you can and cannot eat ingrains that kind of self control, requiring us to learn to control even our most basic, primal instincts.
Donin also points out that the laws of kashrut elevate the simple act of eating into a religious ritual. The Jewish dinner table is often compared to the Temple altar in rabbinic literature. A Jew who observes the laws of kashrut cannot eat a meal without being reminded of the fact that he is a Jew.
If you are interested in keeping kosher, or for more information, check out the following sites:
http://www.jewfaq.org/kashrut.htm
http://www.oukosher.org/
http://www.kosherquest.org/