A Brief for the Defense

I was reading the November 15 New Yorker, and I came upon this poem:

A BRIEF FOR THE DEFENSE

Sorrow everywhere. Slaughter everywhere. If babies
are not starving someplace, they are starving
somewhere else. With flies in their nostrils.
But we enjoy our lives because that's what God wants.
Otherwise the mornings before summer dawn would not
be made so fine. The Bengal tiger would not
be fashioned so miraculously well. The poor women
at the fountain are laughing together between
the suffering they have known and the awfulness
in their future, smiling and laughing while somebody
in the village is very sick. There is laughter
every day in the terrible streets of Calcutta,
and the women laugh in the cages of Bombay.
If we deny our happiness, resist our satisfaction,
we lessen the importance of their deprivation.
We must risk delight. We can do without pleasure,
but not delight. Not enjoyment. We must have
the stubbornness to accept our gladness in the ruthless
furnace of this world. To make injustice the only
measure of our attention is to praise the Devil.
If the locomotive of the Lord runs us down,
we should give thanks that the end had magnitude.
We must admit there will be music despite everything.
We stand at the prow again of a small ship
anchored late at night in the tiny port
looking over to the sleeping island: the waterfront
is three shuttered cafes and one naked light burning.
To hear the faint sound of oars in the silence as a rowboat
comes slowly out and then goes back is truly worth
all the years of sorrow that are to come.

-Jack Gilbert

Okay, now that you have read this, please help me. I'm unable to catch the tone. Is he serious? Is it irony? It was the line, "...we enjoy our lives because that's what God wants" that first pulled me up. Maybe the fact that I don't share this belief kept me from being able to understand. Parts of the poem make sense to me -- I believe that one should try to face this terrible world with as much delight as one can muster. But should one give thanks when the locomotive of the Lord runs one down?

Is this really a brief for the defense? Or for the prosecution? I don't usually feel at such a loss. I'd be very interested in your comments on this poem, especially on what you think the author intended.

(Read twelve more poems by Jack Gilbert at the plagiarist poetry archive. I particularly like one of them, The Forgotten Dialect Of The Heart.)