Leviticus 18:23-25

²³And you may not have sex relations with a beast, making yourself unclean with it; and a woman may not give herself to a beast: it is an unnatural act.

²⁴Do not make yourself unclean in any of these ways; for so have those nations whom I am driving out from before you made themselves unclean:

²⁵And the land itself has become unclean; so that I have sent on it the reward of its wrongdoing, and the land itself puts out those who are living in it.