Sins vary not only in kind but also in degree. While any sin committed is terrible in its unrighteousness, rebellion, pollution, and punishment, (for only one transgression makes us guilty lawbreakers in God's sight), there are degrees of sin. Sin and its punishment increase in degree according to the knowledge, opportunities, and blessings given to a person.
When preaching on earth, Jesus clearly warned the cities of Chorazin, Bethsaida, and Capernaum, where He frequently spoke, with the following powerful message:
Then began He to upbraid the cities wherein most of His mighty works were done, because they repented not: Woe unto thee, Chorazin! woe unto thee, Bethsaida! for if the mighty works, which were done in you, had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes. But I say unto you, It shall be more tolerable for Tyre and Sidon at the day of judgment, than for you. And thou Capernaum, which art exalted unto heaven, shalt be brought down to hell: for if the mighty works, which have been done in thee, had been done in Sodom, it would have remained until this day. But I say unto you, That it shall be more tolerable for the land of Sodom, in the day of judgment, than for thee (Matthew 11:20-24).
Why should the punishment ascribed to the citizens of Tyre, Sidon, and Sodom be more tolerable than that pronounced upon those of Chorazin, Bethsaida, and Capernaum? How does this relate to the degree of knowledge, opportunity, and blessing received?
The worst degree of sin mentioned in Scripture is the unpardonable (or unforgivable) sin. This sin is also called the sin against the Holy Ghost. When using the term "the sin against the Holy Ghost," distinction must be made between pardonable sins, and the unpardonable sin against the Holy Spirit. Scripture speaks of vexing the Spirit (Isaiah 63:10), lying to the Spirit (Acts 5:3), grieving the Spirit (Ephesians 4:30), quenching the Spirit (I Thessalonians 5:19), and resisting the Spirit (Acts 7:51). All of these are sins against the Holy Ghost, but they are not the unpardonable sin.
The unpardonable sin is a sin which Scripture teaches is unforgivable, after which a change of heart is impossible, and for
Tolerable - Capable of being endured or suffered
Vexing - Provoking
Quenching - Extinguishing; suppressing; stifling