In Flanders fields the poppies blow
Between the crosses, row on row,
That mark our place and in the sky,
The larks, still bravely singing, fly,
Scarce heard amid the guns below.
We are the Dead; short days ago
We lived, felt dawn, saw sunset glow,
Loved and were loved, and now we lie
 In Flanders fields.
Take up our quarrel with the foe!
To you from failing hands we throw
The torch; be yours to hold it high!
If ye break faith with us who die
The literal interpretation of this is that the “foe” is the opposing side in the Great War. Another, less obvious interpretation, is that this could be the powers that failed to find agreement peacefully. 
 While not being beligerant there is an assertiveness in the exclamatory command, with its exclamation mark at the end. 
 Is McCrae giving a conscious nod to Kipling (“Take up the White Man’s burden”) with the wording of this injunction?  Kipling’s  poem  was published in 1899, not long before World War One.