This poem is about inner struggle. It’s compared to the struggle of a soldier fighting for one’s country – this is admirable but a person overcoming conflict within themselves can be just as great.
“To charge within the bosom” this line indicates an internal battle – one that the individual must fight by themselves. There is a lot to truth to this. Although help is nice there are some issues that a person must sort out from within and I think that’s essentially what the poem is saying.
Humans tend to crave approval. They want to be encouraged and told when they’re on the right track. However, as the poem shows with these lines like these: “Who win and nations do not see,” “Who Fall and none observe” they won’t always get recognition and they must accept that. Basically, if they’re only looking for outside approval then they cannot truly improve.
The poem can also apply to people who fought on the outside (like soldiers fighting for their country) and then must deal with the internal conflict it has caused them.