To sin literally means “to miss the mark.” This includes acting or even thinking about something that disobeys God’s laws of love. Jesus explained God’s laws in Matthew 22:37-40: “Love the Lord your God with all your heart and with all your soul and with all your mind. This is the first and greatest commandment. And the second is like it: Love your neighbor as yourself. All the Law and the Prophets hang on these two commandments.”  (Matthew 22:37-40)

Concerning any difference in types of sin, James writes in James 2:10: (italics added) “For whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it.”   

We know “death came to all men, because all have sinned” (Romans 5:12).  We also know the “wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord” (Romans 6:23). Our only hope for life after death is the ransom price for Adam paid by Jesus (1 Timothy 2:5,6). Likewise, our only hope for a continued relationship with our Heavenly Father is also through faith in Jesus. 

1 John 1:9: “If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.”  

In the Old Testament, there was a difference in dealing with sins of ignorance (or “negligence” or “frailty”) as opposed to presumptuous (or “deliberate, unrepentant”) sin. (See Smith’s Bible Dictionary under the topic of the “Sin Offering.”)  Numbers 15:27 teaches that if a person sinned unintentionally, he would bring a year-old female goat for a sin offering. The priest would make atonement, and the person would be forgiven.  However, Numbers 15:30 reads, “But anyone who sins defiantly blasphemes the LORD, and that person must be cut off from his people.”  Soon after this command was given to the people, a man was found gathering wood on the Sabbath and was brought to Moses and Aaron, because “it was not clear what should be done to him. Then the LORD said to Moses, the man must die” (Numbers 15:32-35). This might seem very harsh. The people who caught the man breaking the Sabbath could not tell what to do with him, but God who reads the heart could no doubt see that the man’s sin was defiant and therefore pronounced his sentence.

In the same way now, while we are promised forgiveness for the sins we are truly sorry for, we must guard our attitude. The Apostle John warned that there is a “sin that leads to death” (1 John 5:16).  Jesus warned in Matthew 12:31-32 about the sin against the Holy Spirit, which will not be forgiven. This is also sometimes called the sin against light or knowledge. Paul describes this sin very well in Hebrews 10:26: “If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left” (See also Hebrews 6:4-6).

From this we see that the greatest sin is one that is committed by a person who has accepted the Lord Jesus as his/her Savior, promised to follow the Lord unto death, received the Holy Spirit, and then through pride and arrogance decides he/she doesn’t need a Savior and turns to a life of defiant sin. There would be no resurrection for that person.

Additional Resources:
Christian Questions Podcast
Episode #1265: “What Sins Can Never Be Forgiven?”
Identifying what unforgivable sins are and their consequences
Preview Video
CQ Rewind Show Notes

“Is it a Sin If I…” (multi-part series on specific sins)