what are the unpardonable sins?

That is an excellent question! So what is unpardonable or unforgivable sin? Let us take a close look at: Mark 3:28-29 (New International Version) 28I tell you the truth, all the sins and blasphemies of men will be forgiven them. 29But whoever blasphemes against the Holy Spirit will never be forgiven; he is guilty of an eternal sin." Mark 3:28-29 (King James Version) 28Verily I say unto you, All sins shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme: 29But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation. The unforgivable sin is a sin against the holy spirit. This sin is committed when one sins in a deliberate manner knowing quite well what he is doing. It is not a sin committed in weakness but deliberately without caring for the consequences. So it is not the kind of sin committed but the attitude towards the sin where there is a rejection of God or evidence of divine backing. Only God knows when a person commits that kind of sin. But if you read the context of Mark chapter 3 you will see that the scribes ascribed the miracles Jesus did not to the power of the holy spirit but to Beelzebub or Satan the Devil. So if a person commits a sin and feels bad and asks for forgiveness, obviously he is not sinning against the holy spirit and in not committing the unforgivable sin.

We judge people according to the yardstick we set for others. According to this yardstick, what is advantageous to us is good; and anything that is disadvantageous to us is bad. We have a similar yardstick for wickedness and righteousness too. In God's sight whatever is sin might not be sin for us; and whatever is righteousness in the site of God we might think it to be sin. God views things in a broader perspective, and we view things in a very narrow perspective. In your posting you are questioning God's decision. You are questioning how and why God chose people to bring forth Christ into this world who according to you were sinners. No, I do not have an idea. I do not know, "what is unpardonable sin?" To know that is only God's prerogative. We might think that eating fruit of knowledge might not be a sin, but in sight of God it was an unpardonable sin. Therefore, he banished Adam and Eve out of Garden of Eden. We cannot sit in judgment over God's decision.

I am a Muslim and I believe there is only one sin,which is unpardonable and that is only POLYTHEISM or Idolatry as per the last Holy book the Quran.

I think the unpardonable sin is blaspheming the Holy Spirit and I think that means either blaming the Holy Spirit for what someone else did, or giving someone else credit for what the Holy Spirit did.

I can only tell you what Jesus the Christ said in the Scriptures. Matthew 12:30-32 "He who is not with me is against me, and he who does not gather with me scatters. And so I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven. Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come. Mark 3:28&29 "I tell you the truth, all the sins and blasphemies of men will be forgiven them. But whoever blasphemes against the Holy Spirit will never be forgiven; he is guilty of an eternal sin." Luke 12:10 "And everyone who speaks a word against the Son of Man will be forgiven, but anyone who blasphemes against the Holy Spirit will not be forgiven." Speaking evil of the Holy Spirit, or assuming to oneself the rights or qualities of the Holy Spirit, or irreverent behavior toward the Holy Spirit are some ways one would blasphemy Him.

God is very forgiving. That's because He loves His children so very much. Of course, for those who do make such unspeakable choices, God will send lessons. Before it's all said and done, one will understand exactly what our choices mean. I'm afraid some have a few very hard lessons to learn. Lessons do not always feel good. They can hurt. It's never about punishment. It's about education. So go ahead, make those awful choices. Get your education. If you can choose such evil and cause so much hurt, you shouldn't mind knowing how it feels.