In John Donne's poem, "A Hymn to God the Father," the themes I find are of sin, repentance, forgiveness (redemption), and hope.
From the very start, Donne speaks of sin and forgiveness. In both the first and second stanzas, he begins with the phrase "Wilt thou forgive that sin..." (In this he exhibits the act of repentance or feeling regret for his sins.) Donne also refers to "sin" in the first three lines of both stanza one and two. He also refers to the endless cycle of sin (with a paradox) by ending both of the first two stanzas with the lines:
When Thou hast done, Thou hast not done,
For I have more.
He says when you're done forgiving my sins, God, you're not done forgiving my sins...for I will have more.
Donne presents several kinds of sin and wonders if God will forgive them. He writes:
WILT Thou forgive that sin where I begun,
Which was my sin, though it were done before?
Wilt Thou forgive that sin, through which I run,
And do run still, though still I do deplore?
In the first two lines of the first stanza, Donne asks if God will forgive his old sins—sins committed before. In the second pair of lines, Donne asks if God will forgive the sins Donne has committed over and again, even while he hates repeatedly committing the sins.
In the second stanza, Donne lists more sins:
Wilt Thou forgive that sin which I have won
Others to sin, and made my sin their door?
Wilt Thou forgive that sin which I did shun
A year or two, but wallowed in a score?
Donne asks God if He will forgive Donne for leading others to commit sins by practicing sinful behaviors himself. Next he asks if God will forgive him for things he has stopped doing in the last couple of years, but practiced for twenty.
Throughout the first twelve lines, Donne points out his sinfulness, asking if God will forgive him, even while he realizes that his imperfections will not leave him but return and need to be pardoned again.
The tone of the last stanza changes, however.
I have a sin of fear, that when I have spun
My last thread, I shall perish on the shore ;
But swear by Thyself, that at my death Thy Son
Shall shine as he shines now, and heretofore ;
And having done that, Thou hast done ;
I fear no more.
In the final six lines, Donne notes perhaps his greatest sin: of fear— that when he dies, his sins will keep him from being saved...that he will "perish on the shore." But God has promised that when one dies, Christ (God's Son) will shine with a light of forgiveness, cleansing the author of his imperfections, interceding for him at that last moment. He infers that God forgives him of this sin, too—knowing that he will be saved, the author is no longer fearful. He has hope that through God's promise of redemption ("being delivered from one's sins") through His Son (Jesus Christ), Donne will not "perish on the shore," and this knowledge wipes away his fear and fills him instead with hope.
For the first two stanzas, Donne speaks of his sin and his repentance of his sin. In the final stanza, Donne describes his forgiveness (redemption) by God, through the sacrifice of His Son—and God's promise of this forgiveness. And, finally, the author has a sense of hope...for he has nothing to fear.