Metaphor’s the soul of poetry:
this incongruous instrument of speech
with which we say one thing,
when we mean quite another:

I wish that Shakespeare, its greatest English user,
had coined a truly English word for it –
or perhaps, those blunt and foursquare Anglo-Saxons
who came before; their words as hand-hewn as are spades –

the word comes from the Greek, and means a transference;
‘My lord, your transference is apt and shrewd…’
no, even that’s but transferred to a Latin stem,
‘carrying across’. Too late to seek some native word –
a ‘thoughtshift’ or a ‘mindmatch’ then?

We wear it down, and make it less
by thoughtless grabbing at the candy-jars
upon the shelves of sweetshops of our speech,
as if to mimic poetry that we haven't earned..

but at its height, a metaphor shines like new light;
bringing together, two images so disparate
and making of their neighbouring, a moment magical in memory
as if we’d never seen the world so brilliant
or so revealing; moments when the mind’s a god,
and life itself a metaphor; a glimpse
that somewhere, two things mentioned meet
under the astonished, single gaze of eternity itself..

Metaphor’s a holy sacrament: one should never dare
to use it without some faint echo, of a moment clear recalled
when that which one refers to, came dazzling bright into the mind
as life transfigured to another world,
time lifted to the timeless;
the radiance of the world’s first day,
Creation, in itself, one glorious godly metaphor..
and nothing ever less than one.

Michael Shepherd

http://www.poemhunter.com/poem/seeking-metaphor/