The dark and deep woods (with apology to Robert Frost)

I've several heights
to climb -even in the night
and here there's not
a single spark of light-

the bitterest winter -wind
how my face it does cruelly bite!
But I have promises to keep
all fear I've to set aside-

the woods are dark and deep
every intruder they dislike
hard words they seem to speak
they are my very blight!

I can't anyhow walk back:
I've promises to keep
several heights still to steep
before I'll find the comfort of sleep