The new and everlasting covenant is to become like God is through the unconditional resurrection of all mankind and, on the condition of complete adherence to the ideal as far as we understand it, forgiveness of past sins, pardon for all sins of ignorance, and continual additional teaching about the ideal through the Holy Ghost. These blessings were purchased with the blood of Christ, who came here and sacrificed himself to fulfill the requirements of the justice of God.
When you are in the state of open rebellion against God, after receiving the Holy Ghost, you are consenting to the death of Christ:
4 For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost,
5 And have tasted the good word of God, and the powers of the world to come,
6 If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.
7 For the earth which drinketh in the rain that cometh oft upon it, and bringeth forth herbs meet for them by whom it is dressed, receiveth blessing from God: (Hebrews 6)
The unpardonable sin is referred to as shedding innocent blood because to willingly sin is to consent to the death of the only man that ever lived without sinning—Jesus Christ.
The blasphemy against the Holy Ghost, which shall not be forgiven in the world nor out of the world, is in that ye commit murder wherein ye shed innocent blood, and assent unto my death, after ye have received my new and everlasting covenant, saith the Lord God; and he that abideth not this law can in nowise enter into my glory, but shall be damned, saith the Lord. (D&C 132:27)
You must avoid this condition at all costs. If you find yourself in it, there is nothing more important for you to do than repent.