Before I say what the unforgivable sin is, I need to explain what it isn’t. Far too many ignorant teachers have rambled on about what they think it is when they actually don’t know. It isn’t a single sin such as saying “mad dog” backwards. Neither is it turning away from God for a season.
Jesus said in Mark 3:29 (KJV) that it’s blasphemy of the holy Spirit. “But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation:”
And what is this blasphemy against the Holy Spirit? Hank Hanegraaff has wisely said that it’s the steadfast resistance to the Spirit’s conviction until death. When Stephen confronted the Pharisees and gave them the history of Israel’s apostasy, he recognized that they refused to listen to him. But it wasn’t him only but the Holy Spirit speaking through him. In Acts 7:51 (KJV), He summed up, “Ye stiffnecked and uncircumcised in heart and ears, ye do always resist the Holy Ghost: as your fathers did, so do ye.”
The reason we can tell that the Holy Spirit was speaking through Stephen, a man filled with the Spirit, is because of what Christ said in John 14:26 (KJV). “But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.”
And as we saw at the first Pentecost after Christ’s resurrection, it was the Holy Spirit preaching through the disciples. When the gospel is proclaimed, preachers are speaking for the Lord and the words from the Bible are those which the Holy Spirit inspired men to write.
I’ll be explaining much more about this topic in my next book called You Think You’re Going to Heaven? Many people, including those who profess to be Christians, resist the Spirit by not obeying and totally following Christ. They’ll be in for a horrible shock on the day of judgement when they find themselves on the left side of Christ with the condemned souls.