Leviticus 20:25-26

You are therefore to make a distinction between the clean animal and the unclean, and between the unclean bird and the clean; and you shall not make yourselves detestable by animal or by bird or by anything that creeps on the ground, which I have separated for you as unclean. Thus you are to be holy to Me, for I the LORD am holy; and I have set you apart from the peoples to be Mine.