Never shared this before, but the strongest "proof" I've seen in my lifetime for the redemptive power of accepting Christ into your life is; my father.
For the first 14 years of my life, my Dad was a bigoted, and abusive monster. We were forced to go to church, and I grew up, in those first 14 years of my life, believing that swift, devastating physical and emotional punishment was what Christianity was about. IOW - I thought that was the Christian way. And I detested/rejected it.
The Summer of my 14th year, my Dad heard a minister give a guest sermon at our regular church. This minister was starting a new Methodist church in Lexington, and various Methodists churches were allowing him to speak to their congregations. My father was so moved by this man's words that, (quoting my father here_, "I realized my entire life had been spent under the illusion that I was a Christian, and it hit my like a ton of bricks that I didn't even know what a Christ filled life was."
We left our previous church and joined this one. For a long time it met in a business that one of the fledgling members owned. And had a tiny congregation of families that had decided to build this together.
I watched my father confess his sins, get Baptized, and publicly accept Christ as his Lord and Savior.
I was unimpressed, and thought, well I've heard various versions of this before, and went to this church because I really had no choice.
From the time my father stood up in front of his family, the church, and the congregation and did as I described earlier, a change in him so profound occurred that I didn't believe it. My father wasn't the same person. But as a kid that had suffered under his "regime" it was hard for me to accept, and I though sooner or later, the old Dad would resurface. That was 46 years ago, and it never did.
I spent most of my life, even after that, as an atheist, and I got into trouble almost constantly, but the way my father handled it was vastly different. It took me a LONG time to come around, but eventually I did, and to this day, the change in my father is probably the cornerstone of my faith.
I'm not going to go into detail about the pre-Christian version of my father, as compared to the Christian version, but it was dramatic enough that here, all of these years later, I'm still amazed by it.