The knowledge and understanding of God should drive a Christian to bear witness of His goodness and grace.
“I am under obligation both to Greeks and to barbarians, both to the wise and to the foolish. So, for my part, I am eager to preach the gospel to you also who are in Rome. For I am not ashamed of the gospel, for it is the power of God for salvation to everyone who believes, to the Jew first and also to the Greek. For in it the righteousness of God is revealed from faith to faith; as it is written, ‘BUT THE RIGHTEOUS man SHALL LIVE BY FAITH.’” Romans 1:14-17