John Donne's "A Hymn to God the Father" is characteristic of the wit and passion displayed in metaphysical poetry. The poem is a prayer made by the speaker to god for forgiveness of his sins.
The first stanza refers to original sin, the sin that according to Christian belief, we all have at birth because we are imperfect. The second stanza refers most likely to a sin that the speaker committed with others or a sin in which the speaker negatively influenced others. In the last stanza, the speaker admits that his sin is fear that he will not be saved or reach salvation. Here Donne puns on the word "Sun" whose light will shine on his eternally, as will God's son's light. The speaker wants forgiveness for all these sins.
However, thoughout this prayer, there are two other puns that give the poem another, more specific reading. The last two lines of each stanza end with "done" and "more." We know that John Donne married Anne More and that he loved her passionately, even though this marriage proved quite costly to his career at court. As a devout Anglican, he felt it important to put god above all earthly things, including his wife, something the speaker finds very difficult to do. In this poem, Donne puns on both his and his wife's names. Read in this light, it is clear what the speaker is most concerned about. God does not have "done" or Donne, as long as Donne loves his wife Anne More, more than he does his god:
When thou has done, thou hast not done,
For I have more.
When he no longer has Anne More, the poet believes, and he himself is near death, he pleads that God will grant him salvation and then he will give himself completely to God.
And having done that, thou hast done.
I have no more.