In this sonnet, the speaker's state of mind is bitter in the first octet (eight lines). He opens with the image of soldiers dying "like cattle," as if they don't matter. It is as if they have simply been sent to a slaughterhouse.
From there, he continues bitterly, as he comments that those who die on the battlefields have no church bells to toll out news of their death, nor "prayers."
Instead of these emblems of civilized life, the dying soldiers are accompanied into death by the angry sounds (the "monstrous anger") of gunfire and the "demented choirs of wailing shells," rather than church choirs. This vision of doomed youth dying coldly in a dehumanized way on the World War I battlefield angers the speaker.
In the second six lines, or sestet, the speaker's state of mind softens. The poem has moved from the battlefield, with all its horrors, to the memories of beloved friends back at home. The speaker exhibits gentleness toward the people the soldiers leave behind: they are the "candles," "the holy glimmers of goodbyes," to the doomed youth. The soldiers will have no palls (funeral clothes) or flowers on their graves, but the remembrances of loved ones will still grace them—the patient minds and the grief symbolized by lowered blinds:
Their flowers the tenderness of patient minds,
And each slow dusk a drawing-down of blinds.
Owens was an anti-war poet who wanted people to know the horrors of the World War I battlefield so that they would be inspired to end all wars, but in this poem, he moves from bitterness to an acknowledgment of the pain of those left behind.