Actually, I've always found Paul's story to be encouraging.
He was a born-in Pharisee (Acts 23:6), a self-righteousness, angry, murderous Pharisee (Acts 22:4), who was competely transformed by Jesus.
1 Timothy 1:14-16: "The grace of our Lord was poured out on me abundantly, along with the faith and love that are in Christ Jesus. 15 Here is a trustworthy saying that deserves full acceptance: Christ Jesus came into the world to save sinners-- of whom I am the worst. 16 But for that very reason I was shown mercy so that in me, the worst of sinners, Christ Jesus might display his unlimited patience as an example for those who would believe on him and receive eternal life."
This formerly proud, self-righteous, hateful Pharisee was changed so much that he wrote:
"If I speak in the tongues of men and of angels, but have not love, I am only a resounding gong or a clanging cymbal. 2 If I have the gift of prophecy and can fathom all mysteries and all knowledge, and if I have a faith that can move mountains, but have not love, I am nothing. 3 If I give all I possess to the poor and surrender my body to the flames, but have not love, I gain nothing. 4 Love is patient, love is kind. It does not envy, it does not boast, it is not proud. 5 It is not rude, it is not self-seeking, it is not easily angered, it keeps no record of wrongs." (1 Cor. 13:1-5)
It seems to me that his life is proof of the fact that if we turn our lives over to Christ (NOT to some organization), it doesn't matter what we were or what we are now but what he can make of us. I think that's what the "new birth" (John 3:3; 1 Pet. 1:23) is all about.