כִּ֣י אֲנִ֣י יְהוָה֮ אֱלֹֽהֵיכֶם֒ וְהִתְקַדִּשְׁתֶּם֙ וִהְיִיתֶ֣ם קְדֹשִׁ֔ים כִּ֥י קָד֖וֹשׁ אָ֑נִי וְלֹ֤א תְטַמְּאוּ֙ אֶת־נַפְשֹׁ֣תֵיכֶ֔ם בְּכָל־הַשֶּׁ֖רֶץ הָרֹמֵ֥שׂ עַל־הָאָֽרֶץ׃
For I am the LORD your God; sanctify yourselves therefore, and be ye holy; for I am holy; neither shall ye defile yourselves with any manner of swarming thing that moveth upon the earth.
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.