A friend of mine who is a Pastor's daughter once said her father was accused of only preaching the same message, and he responded that it was not his choice, but God's, and that God had only told him to speak on that issue.
In my own personal religious life, a similar situation has occured. I am unable to overcome a sin, the proverbial thorn in the flesh, and God and/or Satan has plagued me (see 1 Chron 21 vs 2 Sam 24) with this constant recognition of my great sin, and thus if I am to write theology, I should write on sin, as it is what I am being taught, through my own faillures.
"Many years ago, in the British TIMES newspaper, the editor asked for comments on what was wrong with the world. Among the many letters which came back to him, was the shortest ever letter to a newspaper editor. It read, 'Dear Sir, I am, Yours faithfully....' The writer was G. K. Chesterton, well-known author of such books as 'Father Brown'. He had put in two words what many of us took years to find out. He meant that what is wrong with the world is a problem of the human heart. The problem is - I am wrong inside. We are all wrong inside. " -(http://www.soon.org.uk/page53.htm)
I admire Chesterton for his honesty and the truth of the statement. Romans 3:23 reminds us 'For all have sinned and fall short of the glory of God" NIV (Catholics pull the Calvinist card out here and read 'all' as 'some', or 'all ... except Mary', and of course we all believe it 'should' read 'all ...except Jesus')
The real point without bringing Marian theology into the equation is that we have all sinned. Sin is a universal reality.
"For God will bring every deed into judgement, including every secret thing, whether good or evil. " - Ecclesiastes 12:14
" I saw the dead, great and small, standing before the throne, and books were opened. Also another book was opened, the book of life. And the dead were judged according to their works, as recorded in the books. And the sea gave up the dead that were in it, Death and Hades gave up the dead that were in them, and all were judged according to what they had done." - Revelation 20:12-13
"I acknowledge, Lord, and I give thanks that you have created your image in me, so that I may remember you, think of you, love you. But this image is so obliterated and worn away by wickedness, it is so obscured by the smoke of sins, that it cannot do what it was created to do, unless you renew and reform it." - Saint Anselm of Canterbury
I've been trying to learn the 'De Profundis', an ancient monastic liturgical prayer in latin, based on Psalm 130. Thus far I have "De Profundis Clamavi Ad Te Domine" [Out of the depths to you I cry Lord]. There are other verses in the Psalm which says "If you, O Lord, should mark iniquities, Lord, who could stand?...For with the Lord there is steadfast love, and with him is great power to redeem. It is he who will redeem Israel from all its iniquities."
Thus God gives us Christ who dies the atoning death and by his blood a propitiation is offered to the Father in forgiveness. Of course the debate is over how this sacrifice is applied to us, forensically, or actually. I again don't feel like entering into this debate right now.
I'd like to focus on 2 things in Christ's commands in the gospels and the pre-Pauline new testament. In these we see 2 ways Jesus, or the Church, describes as ways of absolving sin instantly.
1. Repentence/Confession. In the story of the Tax collector and the Pharisee the famous prayer 'Lord have mercy on me a sinner' is prayed by the sinful tax collector, and Christ says 'that man went home justified'. Likewise Christ gives to the apostles the power to forgive or retain the sins of individuals on his behalf (John 20:23).
2. Baptism. Acts 2:38, the first sermon of the Church given by Pope St. Peter, or Peter, or Simon - The guy has alot of names - but the point is when he says "'Repent, and be baptized ... for the remission of sins, and ye shall receive the gift of the Holy Ghost." The other day my Uncle was waxing philosophical about how the greatest sin of the Catholic Church was infant baptism, I doubt he knew that the Anglican, Lutheran, Reformed, Presbyterian, Orthodox, Coptic Churches along with every church before 1500 AD baptized infants. The ironic thing in the early church for those arguing in favor of adult baptism from those cases of people being baptized later in life, is that Constantine and others - many others - in the early church, believed that baptism forgave you of all your sins, so it was best to do it right before you died, to 'make sure' that they were forgiven. That's where the debate raged. So ironically, the people believed so strongely in regenerative baptism that they didn't want to baptize infants at first, thinking that forgiveness was a difficult thing to come by later in life - hence the growth of the sacrament of Penance (or whatever happier modern name you call it).
So I've been baptized, and I wait for Confession, it can't come soon enough.