Leviticus - Chapter 11

This chapter sets out the clean animals (which may be eaten) and the unclean animals (which may not be eaten).  In setting out these rules God is making it clear that he wants his chosen people to be clean and set aside for him.  He says  (in verses 43 to 45):

"Do not defile yourselves by touching them. You must not make yourselves ceremonially unclean because of them.  For I am the Lord your God. You must consecrate yourselves and be holy, because I am holy. So do not defile yourselves with any of these small animals that scurry along the ground.  For I, the Lord, am the one who brought you up from the land of Egypt, that I might be your God. Therefore, you must be holy because I am holy."

In his first letter, Peter refers to this passage, and links it to following Jesus:

"So prepare your minds for action and exercise self-control. Put all your hope in the gracious salvation that will come to you when Jesus Christ is revealed to the world.  So you must live as God’s obedient children. Don’t slip back into your old ways of living to satisfy your own desires. You didn’t know any better then.  But now you must be holy in everything you do, just as God who chose you is holy.  For the Scriptures say, “You must be holy because I am holy.”"