How can you become a Christian? A Christian is a person who is a follower of Jesus and believes in him. The Bible offers a clear answer so you can know you are a Christian. When a man asked Jesus how to have eternal life, he said, "God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life" (John 3:16). Those who believe in Jesus will have eternal life.