Scripture says, that when we chose to give our allegiance to God, he dealt with the penalty of our sin. Christ’s death prepare the way. And with our allegiance, God applied the results of Christ’s death to us. He nailed our sins to the cross.
When a criminal was crucified, a sign was nailed to the cross listing the crimes the person committed, for which he was being executed. Well, God listed our sins, and nailed them to Jesus’ cross. He was executed for our sins.
Christ has paid the penalty for our sin. The cross cancelled that penalty. And we are now free to approach God, as his child, as his friend, and as his priest.