For some context of the poem: John McCrae was a poet, soldier, and physician. This poem was written in 1915 as a tribute to those who died in a World War I battle fought somewhere in Belgium, where the author treated several soldiers. The poem is describing the tragedy of the soldier's deaths, and talks about the question of the next generation's responsibility to continue the battle of the soldiers.
In the third stanza, the author is asking the readers to continue their fight. The struggle of the war is like a torch they are passing on since they cannot hold it anymore. The readers are to take this responsibility seriously. If the reader does not continue the soldiers fight, the speakers will not be able to rest peacefully, even thought their graves are covered in gorgeous flowers.
