Philippians 3:7-9 "But whatever was to my profit I now consider loss for the sake of Christ. What is more, I consider everything a loss compared to the surpassing greatness of knowing Christ Jesus my Lord, for whose sake I have lost all things. I consider them rubbish, that I may gain Christ and be found in him.."
Mark 10:25 "It is easier for a camel to go through the eye of a needle than for a rich man to enter the kingdom of God."

God's grace is probably one of the most beautiful concepts in the bible. It means that whatever you've done in the past, none of it matters. All of your past sins are washed away with the blood of Jesus, who died on the cross for your sins. But what Paul is saying in these verses is that your sins aren't the only thing that is washed away. Your entire reputation is also washed away. You are a new creation in Christ.
This is a powerful revelation. God can use all of us. We just have to forget everything that we've done and seek only God's will for our lives.