I believe that the gospel is this:
God: God is a perfect, righteous, and holy God, Creator of all things. As Creator, God decides what is right and wrong, and is the ultimate Judge.
Man/Sin: We do sin, and are sinful. We are not worthy to be in the presence of this holy God, and in fact are, naturally, opposed to God.
Jesus: Jesus Christ is fully God and fully man, and came to Earth to live the perfect live that we need to live, and died on the cross a death we deserved to die. He then rose from the dead three days later, and is Savior and Lord, and King of all the Earth.
Response: This truth is not something that one can be neutral towards. One must take a stance, either to submit to and treasure God, or to continue as an enemy of God. God calls us to repent, a word which means to turn from our sins and ask forgiveness of transgressing God’s perfect commands. He also tells us to believe that Jesus Christ is Savior and did all that He says, and belongs rightfully as King of our lives.