Ha'azinu: Chapter 9
The three heads of Atika

We learn about the three heads that are imprinted one inside another and one over another. One of these is concealed Chochmah, one is the most hidden Atika Kadisha and the third is absolutely incomprehensible. Rabbi Shimon talks about the hairs that come out of the skull of Arich Anpin; we learn that the hairs are all smooth and equal in weight. He says that Atika always abides in the thirteen attributes of Mercy.