[I want to say that the ideas in this post come from Tim Keller.]
Most people think there are two ways to live. And many churches and pastors teach that there are two ways to live.
God's Way or Your Way. Religion or Irreligion. Moralism or Relativism.
Often times we think this way, but for certain the people you come into contact with every day think this way: your life group members, co-workers, neighbors, family members, and friends from your club-of-choice.
Often times your lost friends fall into the second camp. They are going their own way. They are their own Lord, and although it may be difficult to see, they are their own savior as well. They are trying to justify their existence in some way or another. If I could just succeed at work... If my kids just turn out ok... I he or she just loved me... If I could just live in that neighborhood... If people liked me... If my dad was proud of me... then my existence would be justified. They don't need to justification through faith because they are their own justification. The only problem is (and it's a big problem) if you come up short there is no forgiveness. As Pastor Tim Keller says, your job can't die for your sins. Jesus is the only savior who, if you get him, will satisfy you completely, and if you fail him will forgive you fully.
Here's where it gets tricky. When you tell your lost friends (and life group members) about the grace found in Jesus, they almost always assume that you are asking them to become really religious, and very moralistic. In short you are asking them to act good. Now who wants to do that!? You have to present them with a third way to live. There is religion. There is irreligion. And then there is the Gospel.
Irreligion is one way of saying, "I don't need God." But there is another more subtle way of saying that you don't need God. And that is by being so good, so moral, so religious, that you feel like God is required to bless you. You have been so good that God owes you heaven. When you are living like this Jesus may be your example, or your teacher, or your sugar-daddy, but he's not your savior. Because you are your own savior. Being incredibly religious is another way of saying, "I don't need God."
People need to hear that the Gospel is neither relativism (I do what I want) nor moralism (I'm so good that God does what I want), but it is something completely different. It is news that we are already justified by God and therefore we love him and worship him and obey him, not because of what we can get but because of how beautiful he is.