I was blessed some time ago by Greg Gilbert’s book What Is the Gospel? This quote in particular struck me as helpful for Christians to consider, as we contemplate our motivation and message when it comes to evangelism:
“Paul insists (in Romans 1) that humanity is not autonomous. We did not create ourselves, and we are neither self-reliant nor self-accountable. No, it is God who created the world and everything in it, including us. Because he created us, God has the right to demand that we worship him. . .
Paul indicts humanity: they have sinned by not honoring and thanking God. It is our obligation, as people created and owned by God, to give the honor and glory that is due him, lo live and speak and act and think in a way that recognizes and acknowledges his authority over us. We are made by him, owned by him, dependent on him, and therefore accountable to him.”
What an excellent summary of why the Christian gospel is applicable to everybody, no matter what culture or background or belief system with which a person may be familiar.
The Christian gospel is not just for Christians, because God is not just the Creator of Christians and because Jesus is not just Lord over Christians. All who are made by God owe God their worship; and Jesus is Lord over all, whether we acknowledge him or not.