The bible teaches that everyone in the world has something which separates them from God, that something is sin.
…….for all have sinned and fall short of the glory of God,…..Romans 3:23 (NIV)
Sin is like pollution in a person’s life which has to be dealt with. God say’s that He deals with Sin through Jesus.
Jesus was sinless and could therefore give His life for those who had sinned.
The cross of Jesus is the answer to the problem of sin.
He himself bore our sins in his body on the tree, so that we might die to sins and live for righteousness; by his wounds you have been healed. For you were like sheep going astray, but now you have returned to the Shepherd and Overseer of your souls. 1 Peter 2:24-25 (NIV)
Jesus died on the cross and came back to life three days later. Because He beat death it also proves that He beat sin. Only Jesus has done this.