All Scripture points to the suffering of Christ Jesus. As Jesus says (Luke 24:46-47), Scripture holds up a picture of God before us that promises grace and forgiveness of sin through His innocent suffering and bloody death. As a consequence, whoever believes in His words and works will be saved from God's judgment and furious anger over sin. However, when sinners hear this message, that all Scripture paints a picture of God's grace and forgiveness of sin for Christ's sake, we reject it. We do not want to be resisted, opposed, judged, or condemned on account of our works, what we have done and left undone, and so we engage in a constant legal battle with God.
We demand that our Creator defend His judgment and justification of sinners in a courtroom where we are judge, prosecuting attorney, and jury. We refuse to take God at His Word. His judgments against us are not true, they cannot be true, otherwise that would mean all our words and works are useless in relation to the eternal, never-changing, supreme judgement of God. And so we resist God's judgment and justification of sinners, because we refuse to be sinners, especially sinful beyond all measure.
This truth is revealed by Jesus' Good Friday affliction and execution. We do not want to admit Jesus dies for sinners even though all Scripture testifies to this fact. We do not want to be justified on account of Jesus' suffering and death because we prefer to be justified by our own suffering and death, especially when it is a death died in pursuit of personal glory. We do not want to be considered sinners because we are convinced, despite all the evidence that God presents which contradicts our position, that God is a liar. God, not us, has a problem with the truth.
This is why John writes that, "If we say we have no sin, we deceive ourselves, and the truth is not in us." (1 John 1:8) Likewise, "If we say we have not sinned, we make God a liar and His Word is not in us." (1 John 1:10) When this becomes our confession it sets us in right relation to Scripture's confession of who our God will be for us, and what Christ Jesus accomplishes for us on the cross.
When we confess that we are sinners we are not running away from God judgment, we are running to His justification: the cross. In the shadow of Christ's cross we confess that there is no truth in us, but that God's truth will win the victory over sin for us. He will overcome sinners by His bloody suffering and death, and so justify them by His resurrection.
It does us no good whatsoever to try to justify ourselves before God. Nothing will come of us summoning God to testify in His own defense in the courtroom of sinful opinion. In the end, all we will hear is that another has died our death for us and that there is nothing we can do to justify ourselves. There is no salvation available to us sinners except the salvation accomplished for us by God, the man Jesus Christ.
We were conceived in sin, birthed into this world in sin, and from our first pitiful wail to our last, we are sinners. But this does not have to terrify us. In relation to Christ, all our sin is made His sin. He becomes Sin to our sin and Death to our death. We may be an evil tree but He is the Master Gardner who hacks at the roots until nothing remains except a tree that bears good fruit, even if the tree itself still suffers through and through from the dry rot of sin.
Therefore, so long as we are sinners (which is to say, this side of the resurrection we are always sinful) we confess, "I am a sinner, this is true. But, for Christ's sake, heavenly Father, forgive me, justify me, and show me the truth of Your Word and work for me."
When we confess our sin we confess God's judgment of us is true judgment. But, it is a wholesome judgment because when God judges us to be sinners it is our justification in Christ. God's judgment and justification of sinners destroys sin and death, it consumes us whole, so that Christ Jesus may be all in all for us. On the cross God made Jesus to be our truth, judgment, justification, sin, death, and resurrection. When we confess our sin we confess that Christ Jesus died for sinners so that grace and forgiveness may be God's final sentence and judgment for all who believe in Christ.