Found it, in WT, but it's 2007, so you and I were long gone (unless it's a rewrite) That was weird, ugh.
2 Yes, it is possible to sin against Jehovah’s holy spirit. “Every sort of sin and blasphemy will be forgiven men,” said Jesus Christ, “but the blasphemy against the spirit will not be forgiven.” (Matthew 12:31) We are warned: “If we practice sin willfully after having received the accurate knowledge of the truth, there is no longer any sacrifice for sins left, but there is a certain fearful expectation of judgment.” (Hebrews 10:26, 27) And the apostle John wrote: “There is a sin that does incur death.” (1 John 5:16) But is it left to the one who has sinned seriously to determine whether he has committed “a sin that does incur death”?
9. What is blasphemy, and what did Jesus say about it?
9 Blasphemy is defamatory, injurious, or abusive speech. Since the holy spirit has God as its Source, saying things against his spirit is the same as speaking against Jehovah. Unrepentantly resorting to speech of that kind is unforgivable. Jesus’ words about such sin show that Jesus is referring to those who willfully oppose the operation of God’s holy spirit. Because Jehovah’s spirit was at work in Jesus but his opposers ascribed this power to the Devil, they sinfully blasphemed against the spirit. Hence, Jesus declared: “Whoever blasphemes against the holy spirit has no forgiveness forever, but is guilty of everlasting sin.”—Mark 3:20-29.