Dying without believing in Jesus is not the greatest sin – though it is a sin. This is because unbelief can be forgiven, as is evidenced by the fact that many people become Christians later in life after rejecting Jesus for many years. But I want to be clear. I’m not saying that if anyone were to die without believing and trusting in Jesus that he or she would be forgiven by God and then go to heaven. There is no second chance in the afterlife. We are told in Scripture that, “it is appointed to men to die once and after this comes judgment, (Heb. 9:27). My point is that unbelief is never considered the greatest sin. It can be and has been forgiven many times when people become Christians. Instead, the greatest sin is Blasphemy of the Holy Spirit because it cannot be forgiven.
“Whoever speaks a word against the Son of Man, it shall be forgiven him; but whoever speaks against the Holy Spirit, it shall not be forgiven him, either in this age or in the age to come,” (Matthew 12:32).
In the context of Matthew 12:22-32, the false religious leaders were attributing the miraculous work of Jesus to the power of the devil. Jesus had been casting out demons and the Pharisees accused him of doing it by the power of Beelzebub. But Jesus says their sin, the blasphemy against the Holy Spirit, would not be forgiven in this age or the age to come. So that is the greatest sin because it has no potential of forgiveness.
When people say dying without believing is the greatest sin they are combining a person’s death with the lack of belief as though those two things are in effect one thing. They are not. Dying without trusting in Jesus is simply dying without him. But all people are obligated to believe and trust in Christ. Jesus commanded us to believe in him. “Do not let your heart be troubled; believe in God, believe also in Me,” (John 14:1). So, dying without believing in Jesus is sin. But, the greatest sin is saying that Jesus did his miracles by the power of the evil one.
