In more detail
As Christians we believe that there is a God who made the world. We also believe that humankind has rebelled against God, and is under his curse (Ephesians 2.1). In a nutshell, the gospel tells us about our misery, God's mercy, and our response to this.
Our misery: sin
God leaves no doubt about our condition. While we set our standards of right and wrong by society's values, God's standard is His own holiness. How do we measure up? "All have sinned and fall short of the glory of God" (Romans 3:23). It is only fair that God demands holiness of us; that is how he first created us. We have rebelled against him as a race and as individuals.
Our pathway away from God has brought its consequences. "The wages of sin is death" (Romans 6:23a). The Bible compares sin to a cruel slave master. There is no mercy in suffering, no freedom from bondage, no lasting joy, no hope for the future. Most frightening is the final consequence of sin. The Bible warns that without God's salvation, death is the doorway to eternal punishment (Hebrews 9:27). It is from this that we need to be saved. From our own sin. From its bondage. From its consequences. "How shall we escape if we ignore such a great salvation?" (Hebrews 2:3).
God's mercy: salvation
God is holy and God is love. His holiness demands that our sin be punished in full. His love provides a way for us to be saved from this punishment. How is this possible? Someone was willing to suffer what we deserve. Our substitute had to be a sinless man, able to suffer the full wrath of God against our sin. The only one able to take our place was God's Son.
The greatest display of God's love unfolded as his Son left heaven to become a man. Born of a virgin 2000 years ago, the Lord Jesus Christ lived with his creation. He was unable to sin, yet he showed compassion to sinners all around him. Men hated Christ because his holiness exposed their sinfulness. They decided to remove him by crucifying him. He willingly allowed them to nail him to a cross of wood outside Jerusalem. They suspended him so they could sit and watch him die. The climax of God's plan of salvation had arrived as God covered the earth with darkness. The Bible tells us that for three hours he laid on his Son the full punishment we deserve to receive for our sin. The darkness was broken when Jesus Christ called out with a loud voice, "It is finished". He had accomplished the mighty work, God's great plan of salvation.
After three days in death, Christ Jesus rose from the dead. This is evidence to all who saw him and to all who read God's word that Christ's suffering completely satisfied his father. He was victorious over death itself - the ultimate consequence of our sin.
God's plan of salvation brings us into the good of Christ's suffering, death, and victory. "You see, at just the right time, when we were still powerless, Christ died for the ungodly" (Romans 5:6). "For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life" (John 3:16).
Our response: service
God now calls us to believe on Jesus Christ. He calls us to confess that we are sinners, and are worthy of his wrath and punishment. He also calls us to accept the sacrifice that Jesus Christ suffered on our behalf. Finally, he calls us to respond to his mercy with thanks, serving him as he commands us to in his word, the Bible.