“The Gospel” is the good news of how people can be reconciled to an offended God. God is perfectly Righteous and Just, He can’t even look upon sin. All humanity lives in rebellion to Him and has no desire to obey His commands. We all lie, steal, disrespect authority, and lust after what we don’t have. Even the “good” things we do are tainted with sinful and selfish motives such as pride. So how can Sinful Us gain a relationship with a Good God? The answer is that Jesus Christ, who was fully God and fully man, took our place and paid for our sins against God with His sinless life, death on the Cross, and Resurrection! If we repent of our sins and trust in only His work on the Cross to save us, then we will have our sins forgiven and fellowship with our Creator restored!
Please follow these links where all of this is more fully laid out and explained:
Unpopular The Movie (A 30 minute film along with lots of resources)
You may also wish to read this sermon by Charles H. Spurgeon: