Rashi on Leviticus
כי אני ה׳ אלהיכם FOR I AM THE LORD YOUR GOD — Just as I am holy, I, Who am the Lord your God, similarly והתקדשתם MAKE YOURSELVES HOLY below on earth ( (Sifra, Shemini, Chapter 12 3),
Or HaChaim on Leviticus
כי אני ה׳ אלוקיכם, "for I am the Lord your G'd." The major difference between Israel and any other nation is that G'd has not described Himself as the "Lord G'd" of any other nation. This obligates us to keep our distance from anything which contaminates us.