All Christians fail to act on their avowed beliefs. Suppose you believed that Heaven exists and that only some of us will qualify to live in it for ever, as the vast majority of Christians claim to. How would this affect your behaviour?
It would depend on what you thought were the admission criteria for Heaven. But whatever you took these virtues to be, they would utterly dominate your life. When everlasting bliss is on offer, nothing else matters at all. People who believed in Heaven would surely act quite unlike those who do not.
Yet the expected behavioural difference is not to be observed. The vast majority of Christians display a remarkably blasé attitude toward their approaching day of judgment, leading lives almost indistinguishable from those of us open non-believers. Put simply, they fail the behavioural test for belief.
An excerpt from this article.