What is the sin against Holy Ghost?
Jesus warned the Pharisees about committing the sin against the Holy Ghost.
This occured under the following circumstances.
Jesus had healed a man, who was blind and mute. The Pharisees were convinced in their hearts that the miracle was of God. Despite this fact, in a blasphemous way, they claimed that it was the work of the devil. It was then that Jesus said: "Whoever shall speak a word against the Son of Man it shall be forgiven him; but whoever shall speak against the Holy Spirit, it shall not be forgiven him, either in this age, or in the age to come" (Matt. 12:32).
The sin against the Holy Ghost therefore includes matters such as these:
A person rejects the Truth even though the Holy Ghost has revealed it to him and convinced him of it. In addition to this a person blasphemes, and takes a determined stance against the conviction created by the Holy Ghost. The sin is not directed against the person of God's Son, but against the office of the Holy Ghost. This sin cannot be forgiven because it is directed against that activity of the Holy Ghost through which He wants to make a person a partaker of God's grace. With this sin a person places himself into a condition from which he cannot be converted.
All resistance of the Holy Ghost does not constitute this particular sin. From the pastoral perspective there is a simple way of determining whether or not a person has committed this sin: Anyone who fears that he has committed this sin has not committed it. We can comfort those who have a troubled conscience concerning this matter with Christ's grace. For when a person is troubled by his sins, this is an indication that the Holy Ghost is working in him and has not abandoned him. Most assuredly the Holy Spirit wants to create and sustain faith in Christ in such a person's heart.
Also today those who stubbornly resist God's Word need to be warned concerning the sin against the Holy Ghost, especially inasmuch as blasphemy is so general and is committed so openly.
Why should we plunge ourselves into eternal damnation when an eternal festival of joy awaits us!