<But in your hearts revere Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect, keeping a clear conscience, so that those who speak maliciously against your good behavior in Christ may be ashamed of their slander. (1 Peter 3:15-16)
To the unfaithful, bring the message casually to those in your general life. For example, everyone can spread the Gospel and defend the faith to their family and friends and make sure never to deny the tenants of Christianity and to make your position well-known and clear to those around you.
<You are the light of the world. A city set on a hill cannot be hidden. Nor do people light a lamp and put it under a basket, but on a stand, and it gives light to all in the house. In the same way, let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven. (Matthew 5:14-16)
Notice that it says that your light (faith) is seen through your good works, not angry and senseless argumentation. Behave in a way that will cause others to want to adopt your lifestyle. You don't do that by being a heated contrarian. It's one thing to have concise, well-informed cases for your position, delivered with understanding and compassion, and another thing to become visibly shaken and outraged by people who hold opinions contrary to Christianity and uncharitable toward them.
Further, I would recommend saving your passion for your field. If you are a teacher, promote Christian values (not facts) in your lessons in addition to your subject. If you are an economist or financial adviser, denounce usury and promote Biblically supported lending practices and methods of making money. If you are a politician, support pro-Christian legislation and public policy. Simply put, get paid to push the culture and economy towards the type of society God desires.
