The answer to this question depends on whether you are a believer in Jesus Christ or not. If you are a believer you can count on the faithfulness of God and the answer is yes, but if you are an unbeliever the answer is sadly no.
For the Believer the Answer is Yes
Here’s part of an answer on Got Questions Ministries website, gotQuestons?org, to the question “Is there any sin that God will not forgive?”
For the born-again child of God, there is no unforgivable sin. All sin was forgiven at the cross. When Christ Jesus said, "It is finished" (John 19:30), that statement meant that the penalty for all sin was paid in full. The word translated "it is finished" is the Greek word “tetelestai.” That word was used in several ways. It was used to stamp "paid" upon a receipt, and it was also the stamp put on a criminal's charges once he had completed his sentence. A "tetelestai" was nailed to the door of his house proving that he had indeed paid in full for his crimes.
There is one condition to God’s forgiveness however. You must come to Him through Jesus Christ and through Him only.
John 14:6 (HCSB) Jesus told him, “I am the way, the truth, and the life. No one comes to the Father except through Me.
Forgiveness is available to everyone who comes through Jesus;
John 3:16 (HCSB) “For God loved the world in this way: He gave His One and Only Son, so that everyone who believes in Him will not perish but have eternal life.
Acts 10:43 (HCSB) All the prophets testify about Him that through His name everyone who believes in Him will receive forgiveness of sins.”
But Born-Again Believers Still Sin
Yes born-again believers do still sin. 1 John was written to believers not and it says;
1 John 1:8 (HCSB) If we say, “We have no sin,” we are deceiving ourselves, and the truth is not in us.
When we do sin we fall out of fellowship with the Lord. However we can renew that fellowship. The Holy Spirit, which the believer receives at salvation convicts us of sin and we have the opportunity to renew that fellowship by confessing our sin, which means agreeing with God, that yes we have sinned. When we do 1 John 1:9 says this;
1 John 1:9 (HCSB) If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness. That's all sins.
Now, remember, this is a letter to born-again believers. God has no illusions about us and our capacity to sin, and we should not either.
The only sins God will not forgive in this age of grace are the sins of those who die without first placing their faith in Jesus Christ. Those who do not take advantage the free gift of eternal life that God has provided through the Lord Jesus Christ. That person will be eternally separated from God and their sins will not be forgiven.
"What is the unforgivable sin, and how do I know I haven’t committed it?”
Mark 3:28-29 (HCSB) 28 I assure you: People will be forgiven for all sins and whatever blasphemies they may blaspheme. 29 But whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of an eternal sin”--
That sin is denying the authority and power of God. In the above verse Jesus was responding to the religious leaders who accused him of casting out demons by Beelzebub, or unclean spirit What they were saying was that His authority came from Satan, not from God. Although these accusers knew that Christ was the Son of God, they accused Him of being a fraud. Christ warned them that they were in danger of committing a sin for which there was no forgiveness.
This is from Lee Strobel’s Investigating Faith newsletter;
“If you’re worried that you may be guilty of the unforgivable sin, you almost certainly are not,”
As the Quest Study Bible puts it, “Jesus gave the solemn warning in these verses to people whose hard-heartedness placed them on the brink of disaster. Blasphemy against the Spirit evidently is not just a one-time offense; rather, it is an ongoing attitude of rebellion – a stubborn way of life that continually resists, rejects and insults the Holy Spirit. This is what makes it, in effect, an eternal sin (Mark 3:29). Blasphemy against the Spirit is not unforgivable because of something done unintentionally in the past, but because of something being done deliberately and unrelentingly in the present.”
So if you’re an authentic Christian, don’t spend time fretting over whether you have accidentally committed this unforgivable offense. “There is no biblical evidence that a genuine Christian can commit this (unforgivable) sin,” says the Apologetics Study Bible.
Salvation Is Free and Immediate
2 Peter 3:9 (NKJV) The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance.
If you have never Jesus Christ as your Lord and Savior there's still time.. It doesn't matter what you've done, how rich or how poor, black, white, red, yellow, Jew or Gentile, salvation in free and available to you right now. All you have to do is ask acknowledge that you are a sinner and that you want forgiveness. You can't change the way that you are and now you are asking God to change you. You can do that right now. Here’s a model prayer you can use.
“Dear God, I am a sinner and need forgiveness. I believe that Jesus Christ shed His precious blood and died for my sin. I am willing to turn from sin. I now invite Christ to come into my heart and life as my personal Savior.”
Once you pray this, or a similar, prayer in all sincerity you will receive salvation.
If you have just prayed this prayer call, text, email, Tweet, change your Facebook status and tell somebody, and leave me a comment. Then find a bible believing church and start to fellowship with other believers. Welcome to the family of God.
You may also be interested in these resources on God's forgiveness