Whenever I begin a unit on poetry, I remark on the virtual impossibility of defining it. For example, compare this sentence:
Just be tender, just be true,
Just be glad the whole day through,
Just be merciful, just be mild,
Just to be trustful as a child,
Just to be gentle and kind and sweet,
Just to be helpful with willing feet,
Just to be cheery when things go wrong,
Just to drive sadness away with a song,
Whether the hour is dark or bright,
Just to be loyal to God and right,
Just to believe that God knows best,
Just in his promises ever to rest –
Just to let love be our daily key,
That is God’s will for you and me.
With this sentence:
The aged sisters draw us into life: we wail, batten, sport, clip, clasp, sunder, dwindle, die; over us dead they bend.
Even though the first sentence is written in rhymed couplets that fall into repetitive metrical patterns, it should not be mistaken for poetry.
A poem should be palpable and mute
As a globed fruit,
As old medallions to the thumb,
Silent as the sleeve-worn stone
Of casement ledges where the moss has grown—
A poem should be wordless
As the flight of birds.
In other words, a poem shouldn’t be a series of non-compressed sing-songy platitudes, nor, I would argue, can it be. Imagine, answering that Nigerian email’s promise of riches “trustful as a child” or approaching a bereaved spouse after a funeral with the advice “just be cheery when things go wrong.” Although jauntily rendered and upbeat in message, the first sentence is life-cheapening because it is false and hollow. What we have is verse, not poetry.
The second example is, literally speaking, prose, a sentence from Joyce’s novel Ulysses when Stephen Dedalus and Leopold Bloom visit a maternity ward where Mina Purefoy has been in labor for three days struggling to give birth to her son. The “aged sisters” are midwives, sisters of mercy, ushering us onto the stage for our hour of joy and sorrow.
Joyce reduces Shakespeare’s “seven ages of man” to eight verbs: wail, batten, sport, clip, cleave, sunder, dwindle, die. And there they are again, a different set of aged sisters, nurses, ushering us out.
Pure poetry, truth compressed, ringing like a bell.
I quoted Joyce’s sentence to two of my colleagues sitting next to each other this morning, one who had lost her aunt last weekend and the other who is about to give birth in a month or so.
“Sorry about your loss,” I said to Megan. “Happy about your gain” I said to Jen. Then I quoted Joyce’s sentence. They both smiled.
I didn’t add, “Just be tender, just be true,/ Just be happy the whole day through.”
 In Ireland, perhaps nuns.