In Luke (9:62) Jesus says: "Anyone who puts a hand to the plow and then looks back is not fit for the Kingdom of God.". I think this expression has multiple meanings. Firstly, that if you turn away from the world to God, you should not continue to live in a worldly way or seek worldly things (or at least try not to). But I suspect it also means we should leave behind our sins. The aim is to not be who we were, but rather to become a new person. This new person is no longer the old sinner who holds the guilt for past sins, but is rather continuing down the path towards becoming an angelic being (like God; remember: Matthew 5:48 “Be perfect, therefore, as your heavenly Father is perfect.”).
Therefore one on this journey is only hindered by holding guilt for the sins of the past. It is in effect like holding the guilt for something someone else has done – positively unhealthy. The Apostle’s Creed (shared by all Christian denominations) includes the following lines:
I believe in the Holy Ghost;
The holy Catholic Church ; (nb: catholic means “all embracing”)
The Communion of Saints;
The Forgiveness of sins;
The Resurrection of the body,
And the Life everlasting.
Notice the line about the forgiveness of sins – you must really believe this to be a Christian. It is a requirement; it is part of believing in the redemptive power of Christ. Therefore do believe it – that once you repent, your sins are forgiven, and you need to move on – focussing not on the past (not looking back from the plough) but working towards eliminating the remaining imperfections in your soul. You must press on relentlessly, and if guilt is holding you back, then at this point one major hurdle you must overcome is your lack of faith in God’s forgiveness and His promise of redemption for determined Christians.