Then I saw my Ba, saw that small bird whose face was my own face, and
I had not seen it since it flew away as my Ka approached its tomb. It was
here above me now, the soul of my heart even as the Ka was my double,
and so the Ba could tell me that purity and goodness were worth less to
Osiris than strength. Such was the thought of the Ba, the purest part of
my heart.
Norman Mailer, Ancient Evenings