I've heard plenty of Christians try to answer the why question by going back to the what. "You have to believe because Jesus is the Son of God." But that's answering the why with more what. Increasingly we live in a time in which you can't avoid the why question. Just giving the what (for example, a vivid gospel presentation) worked in the days when the cultural institutions created an environment in which Christianity just felt true or at least honorable. But in a post-Christendom society, in the marketplace of ideas, you have to explain why this is true, or people will just dismiss it.
Timothy KellerIt is one thing to say that science is only equipped to test for natural causes and cannot speak to any others. It is quite another to insist that science proves that no other causes could possibly exist. . . . There would be no experimental model for testing the statement: 'No supernatural cause for any natural phenomenon is possible.' It is therefore a philosophical presupposition and not a scientific finding.
Timothy KellerChrist's resurrection not only gives you hope for the future; it gives you hope to handle your scars right now.
Timothy KellerReligion operates on the principle 'I obey-therefore I am accepted by God.' But the operating principle of the gospel is 'I am accepted by God through what Christ has done-therefore I obey.'
Timothy Keller