Why does God not forgive all sin?

Why does God not forgive all sinners and sins? I believe that God does personally forgive all sin against him. However, there is the matter of justice.

God as a personal being can choose to forgive whatever he wants. But God as the perfect judge, MUST provide justice for all sin.

Keep in mind forgiveness is one thing. Justice is another. You can have forgiveness and not have justice. Also, you can have justice without forgiveness. If you forgive someone that commits a crime against you, that does not mean that they should not receive justice. God is the perfect judge, so there must be justice for all sins (a sin is a crime against God.) Most people recall that “God is all loving”, but not everyone recalls that God is the perfect judge.

Everyone sins. The sentence (i.e. the justice) for all sin is death (i.e. being sent away from God.) However, Jesus paid your sentence by dying on the cross, so that you may be with God. This is the God News (Gospel) of Jesus.

When you reject Jesus, you are rejecting his payment for your sin. Hence, when you reject Jesus, you receive the justice for your sin. After your death there are only two options for you to receive. Grace or Justice. Grace is Jesus' payment for your sins. Justice is being sent away from God.

“but whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of an eternal sin” (Mar 3:29)

The Greek for forgiveness (ἄφεσιν) in this verse also means pardon or freedom from bondage. So, at the time of judgement, one can be forgiven for rejecting God, but not pardon for rejecting God.