Who can say wherein lies the witchery of this word-music! It can only be felt. In addition to the common meaning of its terms, therefore, language seems to have a further expressiveness. This new significance is the creation of the poet, wrought out of the familiar words by his cunning manipulation of them. The wonder of the poet's craft is like the musician's, —
That out of three sounds he frames, not a fourth sound, but a star. 
THE ONENESS OF CONTENT AND FORM
Poetic form rouses the whole being to sympathetic action by its rhythm; it delights the ear by its melodious tone; the logic of its coherent harmonic structure satisfies the mind; its word-images stimulate the imagination by their power of evocation. So poetry adds to fact its intellectual worth and all the emotional value inhering in it. Finally form and meaning become one. And most intimately so in lyric poetry. Here we feel that just this idea could not be expressed, just that emotion could not be communicated, in any other way. The essence and mystery of the song are in the singing.
A poem is a fragment of life rounded into momentary completeness. It compels the chaos of immediate sense impressions into forms of beauty, and so it builds a fairer world. It catches the rhythms that pulse at the mighty heart of things and weaves them into subtle and satisfying patterns; its verbal melodies waken in the soul dim echoes of the desired music of the spheres. It floods life with unaccustomed light. But it is illusion only in that it sees beyond the changing shows of nature and discerns the loveliness which the human spirit would fain believe is the vesture of the Eternal. Poetry is not illusion, but rather the express image of a higher reality. The poet would compass life and utterly possess it. Not as a patient observer of nature's processes, not a passive spectator of the moving play of human fate, he loves what he beholds. To him, as to a lover, the world yields something of its secret. By force of imaginative, creative vision, he sees life in its wholeness, though but for an illumined moment. Emotion and insight fuse into an image of perfection. To the poet truth reveals itself as beauty.
- Browning's "Abt Vogler," H. C., xlii, 1100-1102.