The Gospel is the good news that Jesus Christ has paid the penalty for men's sins, allowing us to have a relationship with God. Christ's death makes it possible to be made free from the bondage of sin, and to live in heaven with God for eternity. Faith in Christ is a requirement of salvation (Ephesians 2:8-9).
God created mankind (Genesis 1:1)
God Himself is holy (1 John 1:5)
God requires holiness of mankind (Galatians 3:10)
God gave mankind the opportunity to choose whether to obey God's laws. Adam, the first man, chose to disobey God's law, and that moment represents the fall of mankind (Romans 5:12).