Ep 4 The story of two friends

A story is told of two friends. One was born again, the other was not. They were very close, shared many things in common and never for once hurt each other. They just knew themselves as good friends who hated evil. They mutually helped one another. The one that was not born again was also highly moral. He could almost not hurt a fly, so their friendship lasted. Then one day, something happened to one of them, and he concluded that his friend was wicked. What happened? Find out. You could be one