"Bent double, like old beggars under sacks,
Knock-kneed, coughing like hags, we cursed through the sludge."
This illustrates that the soldiers are crippled and mentally defeated. The soldiers are "knock-kneed" as they are worn out and tired, they are "coughing like hags" because of the dreadful conditions in the trenches. "Cursed" connotes that the sludge they are walking through is thick and tricky to walk through. The fact that they were "cursing" shows the idea that they were held down by the sludge but determined to reach their ‘distant rest’. Here as in the rest of the poem there is evidence of an understatement.
"But limped on, blood-shod.
All went lame; all blind.
Deaf even to the hoots
Of tired, outstripped Five-Nines that dropped behind."
"Blood-shod" suggests that they are all injured and are/have been bleeding and that they are covered in blood. Particularly there, suggesting they are unable to get rid of the fact they are at war or the horrendous memories that cling to them. The soldiers have now reached the point that they have become desensitized through fatigue to the dangers of the war. The place is obviously very dangerous as "Five-Nines" are very explosive shells a 5.9 calibre. No-one is left untouched by this experience. The poet shows the panic of the soldiers at the start of the second stanza by using reported speech.
"Gas! Gas! Quick, boys! - An ecstasy of fumbling"
The poet repeats the word gas because he wants to connote the idea of people shouting and panicking and to draw us straight