The poet named in the episode:
Howard Arnold Walter, who wrote in 1906:
The poem is “I Would Be True.”

“I would be true for there are those who trust me.
I would be pure for there are those who care.
I would be strong for there is much to suffer
and I would be brave for there is much to dare.”

There are two other verses. Read them here:
http://www.musicanet.org/robokopp/usa/iwouldbe.htm

The website:
American Folksongs /
Volkslieder aus den Vereinigten Staaten
Folksongs, Hymns and Spirituals of America