The core message of the gospel is that Jesus died on the cross to pay the price for our sins. He did this so we can have eternal life and a relationship with God. But why did He have to die? And more importantly, what sins and whose sins did He die for?
An understanding of God's judicial system would make this post easier to grasp.
Here's the breakdown:
God created man (Adam & Eve) in His image and likeness. Man was totally perfect just like God.*
Adam disobeyed God's instruction. As a result, he was no longer perfect*. Man was now a sinner and the punishment for His sin was death. (Law 1 & 2)
In accordance with Law 3, everyone on earth inherits Adam's sinful nature and his status as a sinner. Like our progenitor, we are not exactly like God. We can never meet God's standard despite our best efforts.
Since everyone is a sinner, we all deserve death and condemnation. (Law 2)
Law 4 of God's judicial system permits the use of a substitute. However, because everyone is a sinner, no one can bear the punishment for others.
The only person who was qualified to be a substitute was God Himself. Now God cannot die (as required by law 5), so He became a man (called Jesus)*.
Jesus died for everyone. He served the punishment for everyone. However, in accordance with Law 6, His selfless act only works for those who voluntarily recognise Him as their substitute.*
Have you accepted Jesus as your substitute?
*Genesis 1: 26 Then God said, “Let Us (Father, Son, Holy Spirit) make man in Our image, according to Our likeness [not physical, but a spiritual personality and moral likeness]” [AMP]
* See Genesis 2 & 3
* 1 Timothy 3: 16 It is quite true that the way to live a godly life is not an easy matter. But the answer lies in Christ, who came to earth as a man, was proved spotless and pure in his Spirit, was served by angels, was preached among the nations, was accepted by men everywhere, and was received up again to his glory in heaven. [TLB]
* John 3: 16 Yes, God loved the world so much that he gave his only Son, so that everyone who believes in him would not be lost but have eternal life. [ERV]