Matthew 12:31–32

The Prophet Joseph Smith:

“He must receive the Holy Ghost, have the heavens opened unto him, and know God, and 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; and from that time he begins to be an enemy” (in History of the Church, 6:314).

Sometimes students are concerned about the sin of blasphemy against or denying the Holy Ghost. President Spencer W. Kimball taught:

“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).

Elder James E. Talmage:

“Jesus was merciful in His assurance that words spoken against Himself as a Man, might be forgiven; but to speak against the authority He possessed, and particularly to ascribe that power and authority to Satan, was very near to blasphemy against the Holy Ghost, for which sin there could be no forgiveness” (Jesus the Christ, 3rd ed. [1916], 269).

Matthew 12:45

President Spencer W. Kimball:

“In abandoning sin one cannot merely wish for better conditions. He must make them. …

“… The things which engaged him and caught his fancy and occupied his thoughts are gone, and better substitutions have not yet filled the void. This is Satan’s opportunity” (The Miracle of Forgiveness [1969], 171–72; emphasis added).

True to the Faith:

“It is not enough to simply try to resist evil or empty your life of sin. You must fill your life with righteousness and engage in activities that bring spiritual power. …

“Full obedience brings the complete power of the gospel into your life, including increased strength to overcome your weaknesses. This obedience includes actions you might not initially consider part of repentance, such as attending meetings, paying tithing, giving service, and forgiving others” (True to the Faith: A Gospel Reference [2004], 135).