Witness Verses
A while ago I put this together as a list of verses which explain the problem (sin), the solution (Christ), and what we must do to be saved. Hopefully it makes sense and flows well.
Problem
There is no righteous person, not even one; There is no one who understands, There is no one who seeks out God; Romans 3:10-11
For since the creation of the world His invisible attributes, that is, His eternal power and divine nature, have been clearly perceived, being understood by what has been made, so that they are without excuse. For even though they knew God, they did not honor Him as God or give thanks, but they became futile in their reasonings, and their senseless hearts were darkened. Romans 1:20-21
Solution
For the wages of sin is death, but the gracious gift of God is eternal life in Christ Jesus our Lord. Romans 6:23
But God demonstrates His own love toward us, in that while we were still sinners, Christ died for us. Romans 5:8
So having overlooked the times of ignorance, God is now proclaiming to mankind that all people everywhere are to repent, because He has set a day on which He will judge the world in righteousness through a Man whom He has appointed, having furnished proof to all people by raising Him from the dead. Acts 17:30-31
Be saved
that if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you will be saved; Romans 10:9
for "Everyone who calls on the name of the Lord will be saved." Romans 10:13
Therefore, having been justified by faith, we have peace with God through our Lord Jesus Christ, Romans 5:1
Therefore there is now no condemnation at all for those who are in Christ Jesus. Romans 8:1
For I am convinced that neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers, nor height, nor depth, nor any other created thing will be able to separate us from the love of God that is in Christ Jesus our Lord. Romans 8:38-39