Read it through once

The essence of a poem is its beauty. It is the object of Poetry to give pleasure. It is not to teach. It is not to preach. A poem must exist as a whole. The true poetical — the truly poetic — sentiment is in its nature ineffable; but we are justified in a definition of that sentiment so far as our definitions can be applied. The success of the poem depends upon the union of tone and harmony — of sentiment and expression — which produces congruity. That congruity is a principle of form; and without form there can be no poem.