A quote from the Padhana Sutta:

"Seeing the bannered force all sides —
the troops, Mara along with his mount —
I go into battle.
May they not budge me from my spot.
That army of yours,that the world with its devas
can't overcome,
I will smash with discernment —
as an unfired pot with a stone."

The Padhanna Sutta is part of the Pali Canon, which are
some of the oldest records we have of the life of the
Buddha and what he may have actually said.
The quote above, specifically deals with his
confrontation with Mara immediately before his
enlightenment.  Mara is a god or demon depending on
your definition who consistently tries to tempt the
Buddha to give up his meditation under the Bodhi Tree
and go home.
He tries reasoning with Buddha,
tempting him with beautiful women, and eventually by
threatening him with an army of demons.  Buddha touches
his hand to the ground and gives the quote above,
which I liked enough to post here.

There are various interpretations of what Mara is.
Even in some of the early Buddhist texts, there's
an insinuation that he might not be an actual being
but the forces of temptation that we all carry
around in our heads.  Other times he's
presented as an actual being.  In either case, Mara
contiually throughout the Buddha's life tries to
tempt him away from the path, and each time fails,
and over time these stories move from being akin to
Jesus being tempted in the desert by the devil,
and more towards a sort of spiritual precursor
to a Road Runner cartoon, with Buddha
recgnizing Mara's tricks for what they are more
or less immediately upon seeing them,
with comical results for the would be tempter.
Not to do with Zen in particular today, but
there's a cool quote about smashing armies and
some talk about being unshakeable in your beliefs,
so there you go.