The Torah tells us that a kosher animal is one which has split hooves and chews its cud; pigs have split hooves, but because they do not chew their cud, are not kosher. The Rabbis of the Medrash tell a parable of a pig stretching out a leap in order to display its split hooves, and attempt to fool everyone into believing that it is kosher.
Esav, Yaakov's twin, claimed to follow the same tradition as Yaakov. When Yaakov left to Padan Aram to marry a girl from the family , Esav followed suit and also married a girl "from the family," but did not divorce his non-Jewish wives. This act of marrying a "girl from the family" was solely in order appear as though he was following in the footstep of Jewish tradition.
The so called "Judeo-Christian" tradition is merely a facade. Despite the fact that the two brothers were twins, and had a lot in common biologically, they had very little in common in terms of lifestyle. There is an often-quoted medrash which states, "Why is the pig called a 'chazir'? Because some day in the future God will give it back ("lehachziro") to the Jewish people." The Rishonim ask how this can be. The Rambam postulates, as one of the thirteen principles of our faith, that the laws of the Torah will never change. Can it be that some day it will be permissible for us to eat Pork?
Some of the Rishonim explained that "the return of the pig does not refer to eating pork, but rather to the restoration of the Jewish government in place of the Christian one." The "pig" is the faker who makes believe that he is kosher by showing his split hooves, just as Christians claim that theirs is a twin-religion with ours, and just as Esav was a twin brother of Yaakov.
The prophet Malachi points out in the haftorah that the fact that they were twins has nothing other than biological significance: "I love Yaakov, while I have rejected Esav, and I disdain him." Throughout the generations the Jewish people have adopted a dual position vis-a-vis the Christians and mankind. Namely, the position of Avraham Avinu (in the beginning of Chayei Sara): we exist as both strangers and citizens with respect to the rest of mankind. Regarding fighting crime, terror, disease, poverty, improving the economy, and delving into the science of nature, we are equal partners, and all work together. But, with respect to the purpose of our lives, and lifestyle - the Jewish people feel "as strangers", and share nothing in common with anyone else. We are "the nation that lives alone" (parshas Balak), and will always remain so. The Jews live alone, die alone, and are buried alone. When Ruth converted and joined the Jewish people, she said to her mother-in-law Naomi, "Where you go I will go; where you stay, I will stay; the way you will die, I will die; and there too will I be buried."
After living for many years in peace and harmony in Eretz Canaan, after the passing of Sara, Avraham Avinu insists on buying her a separate burial plot. The Jew lives differently, dies differently, and is even buried differently to emphasize this point. We share biological similarities with others, and work together with others on many different projects for the purpose of improving man's position here; but we do not share their weltanschauung. "Asher bochar banu mikol haamim."