From Thich Nhat Hanh, the Vietnamese Peace Activist, Author, Poet.
These words are called gathas, short verses that help us practice mindfulness in our daily activities:

Breathing in, I know I am breathing in.
Breathing out, I know I am breathing out.

As the in-breath grows deep,
The out-breath grows slow.

Breathing in makes me calm;
Breathing out brings me ease.

With the in-breath I smile;
With the out-breath I release all tension.

Breathing in I know I am alive;
Breathing out, in this present moment.

Breathing in, there is only this present moment.
Breathing out, it is a wonderful moment.