The poem opens with a guy telling a maiden not to weep over her dead lover because war is kind; soon after, the scene changes and we're on a battlefield. The speaker remarks that the soldiers in front of him were born to drill and die; the battle-god is great, he notes.
The scene changes again and the speaker addresses a babe whose father died in a trench somewhere; he tells this little guy not to weep because, you guessed it, war is kind. We again visit the battlefield, where the speaker makes a number of similar remarks about the destiny of his soldiers.
In the poem's final stanza, he addresses a mother, who stares silently at the body of her son, which is covered with a shroud. "Do not weep, war is kind," he tells her. Thanks a lot, buddy.