What do I really believe will change the world for good?

I am astonished that you are so quickly deserting the one who called you to live in the grace of Christ and are turning to a different gospel—which is really no gospel at all. Evidently some people are throwing you into confusion and are trying to pervert the gospel of Christ.  But even if we or an angel from heaven should preach a gospel other than the one we preached to you, let them be under God’s curse!  As we have already said, so now I say again: If anybody is preaching to you a gospel other than what you accepted, let them be under God’s curse!  Galatians 1:6-9 (NIV)
Questions to ponder:
Am I confident that trusting Jesus is all I need to be right with God?
What do I really believe will change the world for good?
I have been crucified with Christ and I no longer live, but Christ lives in me. The life I now live in the body, I live by faith in the Son of God, who loved me and gave himself for me. Galatians 2:20 (NIV)