I always believed in God, I would go to mass most of the time, but I had no idea of the calling to holiness.
Your source material is the people you know, not those you don't know, but every character is an extension of the author's own personality.
I try to write in plain brown blocks of American speech but occasionally set in an ancient word or a strange word just to startle the reader a little bit and to break up the monotony of the plain American cadence.