Death and Futility
Owen drives home his anti-war message by showing how futile and meaningless these deaths really are. In "Tonight, this frost will fasten on this mud and us, shrivelling many hands", he places soldiers on the same level as mud - suggesting their deaths bring no glory or honour.
The verb "shrivelling" is particularly powerful because it's usually associated with elderly, frail people. This shows how war has sucked all the vitality out of these young men, making them vulnerable and fragile.
"Sudden successive flights of bullets streak the silence" uses brilliant sibilance to mimic the actual sound of ammunition whistling overhead. But here's the killer detail - even these bullets are "less deadly than the weather".
The modal verb "will" expresses absolute certainty about their inevitable deaths. Owen reinforces this futility through "For love of God seems dying" - the soldiers are losing their faith because they can't understand why a loving God would allow such suffering.
Context: Owen's brief career in the Church influenced his view of religion as hypocritical, which explains why he questions God's love in the face of such senseless death.