The poem is made up of three stanzas each beginning and ending with the title line. Each stanza reinforces the underlying theme of the poem which is the transformation of life and material bodies in other forms that belie death.
The first stanza is about the unity that the dead achieves with the universe. Death is therefore only a superficial event, the spirit of life continues in its wholeness with the universe. This contrast between material and immaterial/spiritual life is well illustrated in line 8 which says that although the bodies of the lovers will be gone, their deep feeling of love will not.
The second stanza focuses on the test that death puts onto human faith. Yet, the third stanza argues that human lives continue in nature, thus going back to the wholeness of the dead with the universe introduced in the first stanza
Though they be mad and dead as nails,
Heads of the characters hammer through daisies;
Break in the sun till the sun breaks down,
And death shall have no dominion.