Ha'azinu: Chapter 43
Aleph, Chet, Hei, Ayin; Gimel, Yud, Caf, Kof

Rabbi Shimon explains in detail how the four letters Aleph, Chet, Hei and Ayin are engraved on the throat and how those four are crowned with the four letters Gimel, Yud, Caf and Kof in the palate. We learn that the important thing is the balance of the three columns, and Rabbi Shimon says that throughout his whole life he was always careful never to receive the left column on its own except for a single instance, at which time he was warned not to do so by a flame of fire.