Help identify a poem -- Timothy Mc Veigh's curious choice

I am trying to find a poem that I vaguely remember memorizing in high school years ago. I want to send it to my daughter in college. The lines I can recall go something like:

"It matters not how straight the path, how charred with punishment the scroll, I am the master of my destiny, captain of my fate."

Can anyone help me find this poem?

"It matters not how strait the gate,
How charged with punishments the scroll,
I am the master of my fate:
I am the captain of my soul."

I've provided a link to the poem at Bartleby.

I believe the poem was also Timothy mc Veigh's choice as his "last words" before receiving the injection. Not that it matters, really, but it's curious how this "crazy mass-murderer psychopath" who's in a big hurry to die was also anything but illiterate.