How can a bird that is born for joy Sit in a cage and sing?

Heaven is in a grain of sand.

I rest not from my great task! | To open the Eternal Worlds, | to open the immortal Eyes of Man | Inwards into the Worlds of Thought; | Into eternity, ever expanding | In the Bosom of God, | The Human Imagination

One Power alone makes a Poet: Imagination. The Divine Vision.

Some say that happiness is not good for mortals, & they ought to be answered that sorrow is not fit for immortals & is utterly useless to any one; a blight never does good to a tree, & if a blight kill not a tree but it still bear fruit, let none say that the fruit was in consequence of the blight.

How can the bird that is born for joy Sit in a cage and sing? How can a child, when fears annoy, But droop his tender wing, And forget his youthful spring?

We are not meant to resolve all contradictions but to live with them and rise above them.