Sin against the Holy Ghost (Matthew 12:31-32)

Some people worry that they might have inadvertently committed the unpardonable sin. In this week’s reading (Matthew 12:31) Jesus teaches: “Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.”

I love this clarification from the Church’s Doctrine & Covenants manual: 

1. Sons of perdition are different from Church members who once had active testimonies of the truth but later fall away from activity and following the principles of the gospel. Sons of perdition commit the unpardonable sin of denying the Holy Ghost.
2. The Prophet Joseph Smith taught the following about the unpardonable sin: “What must a man do to commit the unpardonable sin? He must 1) receive the Holy Ghost, 2) have the heavens opened unto him, and 3) know God, and 4) then sin against him. After a man has sinned against the Holy Ghost, there is no repentance for him. He has got to say that the sun does not shine while he sees it; he has got to deny Jesus Christ when the heavens have been opened unto him, and to deny the plan of salvation with his eyes open to the truth of it” (in History of the Church, 6:314).
   
   Committing the unpardonable sin requires a special knowledge of the Savior gained through a sacred experience with Him. President Spencer W. Kimball helped us understand what this means for most members of the Church: “The sin against the Holy Ghost requires such knowledge that it is manifestly impossible for the rank and file to commit such a sin” (The Miracle of Forgiveness [1969], 123). (Source)
   
   Plus Hebrews 6:6 clarifies that sons of perdition are those who “crucify to themselves the Son of God afresh, and put him to an open shame.”

So have you committed the unpardonable sin? Unless you have had a personal and sacred experience with Jesus and then denied your testimony while still knowing it to be true, and would be willing to crucify Christ again. . . then, no. Hooray! (Source)