God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them. (II Cor. 5:19)
God has already forgiven the entire human race because of Jesus Christ. Because Jesus Christ has FINISHED His redemptive work, God is finished forgiving. And His forgiveness is total for every sin ever committed, or that will be committed, by every human being.
Our faith does not contribute to this finished work. Nor can our unbelief undo it. It is a finished reality for the entire human race in Christ — regardless of whether even one person believes it or not. But it is only those who DO believe that are saved — only those who believe are joined to the Lord and made one with Him in His death and resurrection; in His finished work.
Faith doesn’t convince God to forgive us. Rather, by faith we embrace the reality that He already has. In short, faith doesn’t finish what is already finished. Rather, faith believes, embraces, and surrenders, to the One in Whom there is redemption.
No one is really going to believe and embrace God’s finished forgiveness for them unless they know they need it. This is why we must be convicted of that need and brought to repentance and to the renunciation of the old life. Faith in Christ is not merely a religious tenet to follow. It is the outcome of seeing the Truth of God in Christ.
The gospel of Jesus Christ states that in Christ God was reconciling the world to Himself – completely apart from our faith or works. That forgiveness is full and final in Christ. God offers Christ freely by grace. But only those who believe will be joined to the Lord and be saved by His life.