Conviction is the work of the Holy Spirit where a person is able to see himself as God sees him: guilty, defiled, and totally unable to save himself (John 16:8). Conviction functions differently for the Christian and non-christian. For the non-christian, conviction reveals sinfulness, guilt, and brings fear of God's righteous judgement. Whereas conviction in the believer brings an awareness of sin and results in repentance, confession and cleansing.
Theologically, conviction is produced by the Holy Spirit (John 16:8), the gospel (Acts 2:37), conscience (Rom. 2:15), and the Law (James 2:9). Conviction of sin brings man to the cross and shows the need for forgiveness.