is a call to arms to McCrae's fellow soldiers. They must rally for their fellow soldiers.

If ye break faith with us who die We shall not sleep, though poppies grow
In Flanders fields.

Overall, the poem touches on the reality of death in battle, but it's an optimistic piece. The poppies mark the place where people died, bright spots in the gloom. The poem addresses those who still live, asserting that they should carry on the torch for their fallen comrades. The themes of life in death are clearly in play here, but the biggest theme is brevity. Life is brief, like a flower's bloom or a lark's song.

One of the primary messages of this poem is the responsibility the living owe to the dead. "The Dead" collectively speak in this poem and recall that just days earlier, they were vibrantly alive. They lived and loved, watching the natural splendor of sunset with their fellow soldiers.

Yet war has robbed them of life. They now lie underground below crosses, forever separated from the singing of the larks and other wonders of nature. They ask that those who are living "take up [their] quarrel with the foe." They have passed the torch of responsibility to those who are still alive to fight the battles that follow, asking that their efforts not be in vain. At first glance, it seems that the speakers ask that those who are living continue to wage war, fighting with the enemy as a means of retribution. Yet there also seems to be a consequence of all this death; after all, in asking the living to continue a war, the dead also ultimately ask for more people to die.

The message is thus complex. Honoring duty and country means that some soldiers will not return from the battlefield. While the living are called upon to continue the battles which have claimed lives, it is also important to remember that war is not glorious. Instead, the totality of its effects are horrific, cutting young lives short and robbing them of the experiences of the living.

This poem, "In Flanders Fields," was written by John McCrae, a Lieutenant Colonel in the Canadian Army during World War I.  He served as a surgeon, and the poem is clearly a reaction to the horrors and death as well as the moments of poignant beauty he experienced during his time of service.  The site I've included gives more background, if you're interested.

The  poem is fairly straightforward.  Stanza one depicts moments of beauty in the midst of death.

In Flanders Fields the poppies
Blow between the crosses row on row
That mark their place; and in the sky
The larks, still bravely singing, fly
Scarce heard amid the guns below.

Poppies are a brilliant red, which is certainly appropriate for the tenor of the poem; otherwise, in this stanza, everything seems so peaceful and calm and normal despite the ravages of war which rage on the ground.  The next line dispels this normalcy with three simple words:

We are the Dead. 

Stanza two goes on to say that just a few "short days ago" these men did everything "normal" people did:

We lived, felt dawn, saw sunset glow,
Loved and were loved, and now we lie
In Flanders Fields. 

The final stanza is a call to arms made from the grave.  Those who have died are passing their weapons and "passing the torch" of their intent to win this war to those who can still fight.  The last lines could possibly be seen as a threat, beginning with the words "If you don't."  Instead, it's more of an encouragement.

If ye break faith with us who die
We shall not sleep, though poppies grow
In Flanders Fields.

This is a typical war poem in the sense that it treats the war as an unpleasant reality.  It is particularly striking, again,  because of that peaceful field of poppies blowing in the wind as soldiers fight and men die. 

On a personal note, I had students memorize this poem one year more than twenty-five years ago, and that haunting image of poppies blowing in a field has stayed with me ever since.