How then shall they call on Him in whom they have not believed? And how shall they believe in Him in whom they have not heard? And how shall they hear without a preacher? (Romans 10:14)
In the Old Testament, God gave laws and instructions to the children of Israel, which they couldn't keep, no matter how hard they tried. But thanks be unto God! All of those laws and commandments have been nailed to the cross. Colossians 2:14 says He blotted out "...the handwriting and ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to the cross."
Not only have your sins been nailed to the cross, what caused them to be sins in the first place have also been nailed to the cross! No wonder Paul said in Romans 6:11, "...reckon ye also yourselves to be dead indeed unto sin, but alive unto God..." To be dead to sin is one part, to be alive to God is another; however, both have been consummated in Christ-- in His works of salvation.
The Bible says Jesus bore our sins on His own body on the cross:
(1 Peter 2:24)
Who his own self bare our sins in His own body on the tree, that we, being dead to sins, should live unto righteousness: by whose stripes ye were healed.
Our sins were dealt with before the resurrection. The resurrection is very important because that's what brought us into life and justification in Christ. Hence, to receive salvation, a man must confess the Lordship of Jesus, and believe His resurrection. Romans 10:9-10 says,
...if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised Him from the dead, thou shall be saved...
Dear Father, thank You for the wonderful works of salvation, consummated by the death, burial and resurrection of the Lord Jesus. Sin, with its cause and effects, has been nailed to the cross; and now, I live triumphantly, displaying Your graces and goodness everywhere, in Jesus' Name. Amen.
Further Study: Romans 5:7-8; Romans 4:23-25; Romans 6:4