A poem is sort of an onion of contexts, and you can no more locate any of the important meanings exclusively in a part than you can locate a relation in one of its terms. The significance of a part may be greatly modified or even in extreme cases completely reversed by later and larger parts and by the whole.
Texts from Housman, p. 21 - Kipling, Auden & Co: Essays and Reviews 1935-1964 (1980)