Through a close examination of the text of Parshiot Achrei-Mot and Kedoshim, we can notice that the structure of the social constitution outlined in the parshiot is twofold, divided between the two parshiot.  Acharei Mot contains the negative prohibitions of arayot (sexual transgressions), and Kedoshim contains the positive social practices which are meant to characterize Jewish society. 

Courtesy of the Virtual Beit Midrash, Yeshivat Har Etzion