The extract is taken from an ode which is called "Intimations of immortality from recollections of early childhood".
In this poem, the poet recollects the imagery from his infancy, a period in which men are used to responding to outside stimula without emotional filtrations. The basic thesis is that when we are born, we come from God, and bring with us the memory of the best situation of close contact with God, which weakens as we grow up. It is important to notice that the Neoplatonic philosophy describes the presence of God as being the greatest state we can attain. As a consequence to that, the more unnatural the life of a man is, the more uncapable he is of perceiving the presence of God.
The speaking voice is remembering a past moment of his life when, because he was very young, his relationships with Nature was spontaneous. The abundant usage of metaphors highlights the freshness of a dream and nostalgy, as well as remoteness from true feelings.