Is there an "Unpardonable Sin"

I believe there is even though no matter how evil our sins, there is pardon for them but,
 The following taken from, InTouch, in part:
God forgave David for his adultery, dishonesty, and murder (2 Samuel 12:13; Psalm 51). Simon Peter’s denial of our Lord accompanied by profanity was forgiven (Matthew 26:74-75). The apostle Paul was forgiven of his merciless persecution of Christians (Acts 9:1). Just about every possible sin is listed somewhere in the New Testament. And every one of them falls into the category of forgivable.

But I believe there is an unpardonable state—the state of continued unbelief. There is no pardon for a person who dies in unbelief. The Bible refers to this in terms of having a hard heart. The hardening of the heart is not a one-time act. It is the progression in which sin and the conviction of the Holy Spirit are ignored. The hardened heart has no desire for the things of God. But if you have desire in your heart for God, demonstrated by your concern that you have committed some sort of sin, you do not have a hardened heart. Your concern confirms your innocence. God always welcomes those whose hearts are sensitive toward Him. The unpadonable sin is when a believer, having been delivered from sin in the past,  falls back into sin and continues to stay in it even through he knows the truth. This is the unpardonable sin.

On the other hand, if you are unsaved, that can be remedied this very moment. Salvation is by faith alone—faith in the death of Jesus Christ for your sin. You can place your faith in Him by praying a simple prayer expressing trust in Christ alone for the payment of your sin. Acknowledge your sin, accept Christ’s payment, receive His forgiveness, and thank Him for the gift of eternal life. "What do you think?"