"What if I told you that there was a book which compiled the themes, anecdotes, and turns of phrase on which you base your everyday life—would you want to know about it? How about a book that contained eyewitness testimony of some of the most legendary events and famous personalities in world history—would you be interested? What if I told you this same book was the very foundation for all of Western Civilization, containing the very principles and precepts upon which democracy and human rights were founded—would you want to read it? You’ve probably caught on that I'm talking about the most well-known collection of books ever compiled: the Bible—by far, the most important piece of writing ever published" (Excerpt from Consider the Evidence pg. 1)
"The Bible is not just a collection of stories; it’s also a historical document. We can use its depiction of history to examine whether the claims made in regard to our souls are true. If those claims are provably false, we need not worry about this subject at all. If they are true, we need to pay careful attention to what the Bible says. In other words, if the Bible is not true, then it's of zero importance. But, if the Bible is true, then it's of monumental importance. The Bible, as set forth in the New Testament, is the foundation of Christianity. To paraphrase what C.S. Lewis said, "the only thing [the Bible] cannot be is moderately important." (Excerpt from Consider the Evidence pg. 4)
The point here is simple: If Christianity is true, follow with your everything (to the best of your ability), if false, completely reject it. The only option you can't take is indifference to the words of God. Jesus even speaks of this In Revelation 3:14–21 where he speaks of the lukewarm believer. "So, because you are lukewarm, and neither hot nor cold, I will spit you out of my mouth." But this same concept can be applied to unbelievers. It's nearly impossible to passively reject something as significant as the word of God.
God calls us to be the people He wants us to be. He should (and we should not) not settle for mediocrity as what He did for us on the cross was nothing short of spectacular. We are obligated to respond to his love and faithfulness to us by expressing it to all people, especially to those who don't believe.