The Reason Why Anne Sexton's "Courage" Poem Is Featured In "To The Bone"

Here's the full text of the poem:

It is in the small things we see it.
The child's first step,
as awesome as an earthquake.
The first time you rode a bike,
wallowing up the sidewalk.
The first spanking when your heart
went on a journey all alone.
When they called you crybaby
or poor or fatty or crazy,
and made you into an alien.
You drank their acid,
and concealed it.

Later,
if you faced the death of bombs and bullets,
you did not do it with a banner,
you did it with only a hat to
cover your heart.
You did not fondle the weakness inside you,
though it was there.
Your courage was a small coal
that you kept swallowing.
If your buddy saved you
and died himself in so doing,
then his courage was not courage,
it was love; love as simple as shaving soap.

Later,
if you have endured a great despair,
then you did it alone,
getting a transfusion from the fire,
picking the scabs off our heart,
then wringing it out like a sock.
Next, my kinsman, you powdered your sorrow,
you gave it a back rub
and then you covered it with a blanket
and after it had slept a while
it woke to the wings of the roses
and was transformed.

Later,
when you face old age and its natural conclusion
your courage will still be shown in the little ways,
each spring will be a sword you'll sharpen,
those you love will live in a fever of love,
and you'll bargain with the calendar
and at the last moment
when death opens the back door
you'll put on your carpet slippers
and stride out.