Firstly, one should understand that this is one of Owen's numerous anti-war poems. This poem, however, differs somewhat from the others because the imagery used here is much more gentle than the harsh descriptors he uses and images he paints in his other poems.
The poem concerns the desperate plea of the speaker that one of his fellow soldiers (most probably someone he has befriended) be moved into the sun.
Move him into the sun—
The dash at the end of this line indicates an expectation. It is as if the speaker, as well as the reader, expects that there will be some kind of a result once the soldier has been moved to lie in direct sunlight.
In lines two and three we are told that the soldier has to be moved because at home, in the past, the sun awoke him gently as he was sleeping. There was the whisper of fields unsown, which implies that the soldier may have come from a rural community, where farmland was his home and fields were not fully harvested yet. The sun in these lines is personified as gentle - its light was not harsh or jarring. This indicates a caring nature. The sun cared for the soldier and it nurtured him just as it nurtured the fields in which he may have toiled.
Gently its touch awoke him once,
At home, whispering of fields half-sown.
The word 'whispering' emphasises the gentle tone in these lines and 'half-sown' also alludes to the youthfulness of the soldier.
Always it woke him, even in France,
The speaker emphasises in line four that the sun's awakening power was not a once off event, it consistently awoke the soldier, not only at home but also here, on the battlefields in France. Once again, an expectation is created - if the sun had so regularly awakened the soldier in the past, it should also awake him now.
Until this morning and this snow.
This line creates a dramatic contrast to the previous lines which were positive. Here, we realise that the sun has suddenly deviated from what it has always done - the word 'until' introduces a dramatic break from the regular pattern of the sun's benevolence. The repetition of 'this' emphasises the shocking realisation that the soldier has not, on that particular day and in those particular conditions, awakened. The word 'snow' suggest the reason why not. It is in direct contrast to the warmth of the sun and has countered its revitalising power.
If anything might rouse him now
The kind old sun will know.
The last two lines of the first stanza expresses a sense of hope. The speaker places his faith in the sun who is personified as kind. He believes that if there is anything that could awaken the still 'sleeping' soldier the sun would know what that is. At this point, the mood is still positive.
We now realise that the soldier has died of the terrible cold and that the speaker is here expressing a futile hope that the sun will revive his friend just as it had done in the past.
The second stanza continues this hopeful tone. The speaker is asked to think about how magically the sun's power brings life to seemingly dead seeds and how it awoke, a long time ago the dead clay of a cold star. The reference alludes to Creation when the earth was brought to life.
Think how it wakes the seeds—
Woke once the clays of a cold star.
Are limbs, so dear-achieved, are sides
Full-nerved, still warm, too hard to stir?
The rhetorical question in lines 10 and 11 implies that if the sun could have had all that power to give life to dead seeds and the clay of an entire star, surely it should be a cinch for it to do the same for this young man? He has not been dead long and his body has been nurtured with care s it cannot be that difficult to revive him.
Was it for this the clay grew tall?
Once again, the rhetorical question is directed to the meaning of life, the purpose of this dead soldier's existence. The question is whether the only reason that this young man grew up was to die on a battlefield. For the speaker the implication is clear, the young man had grown to fulfil a senseless, meaningless purpose. He expresses his anguish and bitterness in the last two lines of the poem:
—O what made fatuous sunbeams toil
To break earth's sleep at all?
In these lines the speaker uses personification and refers to the sunbeams as 'fatuous' which means foolish. He wants to know whether the fact that the soldier had to die was the only reason reason the sun had created life at all? Wilfred Owen asks a deeply philosophical question here: Are we created just to die? As far as he is concerned, if that is so, then man's existence is without purpose and the creation of life an exercise in smugness.