Does our sin disqualify us from things? If I were a thief would that mean I can never be a bank teller? If I were a former drug dealer could I never be a lawyer or police officer?
I have done bad things in the past in the profession I currently hold but have repented and no longer do those things. I’m afraid, because I’ve never been caught and never punished by being in jail or fired (although these things happened years ago), that I don’t deserve to be able to hold employment. In my mind, I reason “if they knew the bad I’d done.“ I feel like the devil may be trying to keep me guilt-ridden, but I remember reading a scripture about a “double-minded man.”
The passage about being a double-mind man is dealing with praying to God for something but not really believing that God is going to answer your prayer. "But if any of you lacks wisdom, let him ask of God, who gives to all generously and without reproach, and it will be given to him. But he must ask in faith without any doubting, for the one who doubts is like the surf of the sea, driven and tossed by the wind. For that man ought not to expect that he will receive anything from the Lord, being a double-minded man, unstable in all his ways" (James 1:5-8).
The world commonly believes that people can't change. That is why you find people arguing that they are "born that way." They have no desire to change. However, Christianity is about radical changes in a person's life. "Do not lie to one another, since you laid aside the old self with its evil practices, and have put on the new self who is being renewed to a true knowledge according to the image of the One who created him" (Colossians 3:9-10). Consider Saul, who was a devote Jew and a zealous persecutor of the church. Few would think that he was just the person needed to spread the gospel to the Gentile nations. "I thank Christ Jesus our Lord, who has strengthened me, because He considered me faithful, putting me into service, even though I was formerly a blasphemer and a persecutor and a violent aggressor. Yet I was shown mercy because I acted ignorantly in unbelief; and the grace of our Lord was more than abundant, with the faith and love which are found in Christ Jesus. It is a trustworthy statement, deserving full acceptance, that Christ Jesus came into the world to save sinners, among whom I am foremost of all. Yet for this reason I found mercy, so that in me as the foremost, Jesus Christ might demonstrate His perfect patience as an example for those who would believe in Him for eternal life" (I Timothy 1:12-16).
Punishment doesn't pay for your past sins. Punishment is used to get a stubborn sinner to realize that he needs to change. You have changed -- that is what is important. As Christians, it is Jesus' blood that cleanses us from our past so that we can live as new people.
"Or do you not know that all of us who have been baptized into Christ Jesus have been baptized into His death? Therefore we have been buried with Him through baptism into death, so that as Christ was raised from the dead through the glory of the Father, so we too might walk in newness of life. For if we have become united with Him in the likeness of His death, certainly we shall also be in the likeness of His resurrection, knowing this, that our old self was crucified with Him, in order that our body of sin might be done away with, so that we would no longer be slaves to sin; for he who has died is freed from sin" (Romans 6:3-7).
"But if we walk in the Light as He Himself is in the Light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin" (I John 1:7).