When Scripture speaks of sin it does not do so as if it were a minor flaw or a series of unfortunate mistakes. The primary Hebrew word for sin means to “miss the mark.” It is important to note that it is the mark that God Himself has set, and not other people for the rest of us. Therefore, sin is not merely failing to live up to our potential; it is falling short of God’s glory (Romans 3.23). It is a rupture in a relationship with God and rebellion in our hearts.
To go along with this, another Hebrew word for sin means to “rebel” or “transgress.” Sin is the willful crossing of a boundary that God has drawn for our good. As Isaiah says, “We all like sheep have gone astray – we have turned everyone to His own way.” (Isaiah 53.6). Sin is self-rule over God’s rule.

The most common Greek word used in the New Testament for sin also means “to miss the mark.” However, it has a bit deeper sense of moral failure and spiritual corruption; corruption that has the power to enslave us (Romans 6.6; John 8.34).
Because sin is rebellion against a holy God, it carries dire consequences – namely death. In the Bible, death is not just the end of physical life, but separation from God who is the source of all life. Because sin destroys our relationship with the Source of our very lives, it only makes sense that it also breaks the bonds of fellowship, confuses identity, and leaves us in a state that we are unable to repair. This is why the Gospel is necessary.
If sin were merely a mistake, we would only need a teacher to correct us. If sin was only ignorance, we would simply need to be better informed to help us change course. If sin was only weakness, then we could overcome it through encouragement and discipline. But sin is guilt, it is corruption, it is rebellion. Therefore, those in sin need a Savior.
The Gospel – the Good News teaches us that God acted in Jesus Christ to deal with sin at its root. Second Corinthians 5.21 states, “(God) made Him who knew no sin to be sin for us that we might become the righteousness of God.” Christ forgives our sin – but He also bears it. Instead of just inspiring us to righteousness – Jesus gives it through His blood.
Jesus did not miss the mark – for His aim is true. He did no sin as He kept God’s law perfectly. Jesus takes our rebellion upon Himself and then submits fully to the Father. He destroys our corruption through His pure life and the cleansing power of His death and resurrection.
Christ is sufficient and that is why (among many other things) that the Gospel is Good News. The Gospel is needed because sin is real. The Gospel is the only message that is needed because Christ is sufficient for all of our needs.