Read the passage from "A Shield.” With brands and billies they beat upon me;
The hard edges hack me; the handwork of smiths
In crowds I encounter; with courage I endure
Ever bitterer battles. No balm may I find,
And no doctor to heal me in the whole field of battle,
To bind me with ointments and bring me to health,
But my grievous gashes grow ever sorer
Through death-dealing strokes by day and night.

Which idea is conveyed by the lines’ format and structure?

the forging of the shield in fire
the cuts the shield has suffered
the power needed to wield a shield
the strength of the metal in the shield