The point of the first stanza is that the value of success feels the best to those who didn’t succeed for a long time. Accordingly one has to seriously want it to be able to understand what success really is. One has to feel “sorest need”. Dickinson points out that people with success often do not appreciate their ability of reaching their goals.
In the second stanza Dickinson then focuses her attention on the field of battle where soldiers fight for land, taking it by “taking and placing their flag”. The wounded soldiers or the “purple Host” are proud of their success even though they won only land by losing the life of men and becoming wounded. The victory might taste bittersweet in contrast to the “sweetness” in the first stanza.
At this point Dickinson switches the perspective to the wounded and dying men of the defeated, clinging to the last bit of their life. The last line describes the sorrow of the man. Ironically the victorious are not able to measure the value of their victory as well as the defeated who hear the music from the distance. The defeat is the loss of the life. The success of the victorious is a piece of earth, the success of the defeated would be just living.
Changing the perspective reveals the different the understanding of the value of success. Something that might be relevant to one might be irrelevant to another. Clearly speaking, the achievement of winning some piece of earth is relevant to the living and not wounded victorious but is of no relevance to the defeated, because they lost their life. The value of victory might be weakened by a lost arm,