From comments on a recent question where I commented that in the sentence given there:
Ich habe eine Frage, die den Gott betrifft.
we usually would not use an article with God. There was considerable dispute on that. My comment there even received a rude/offensive flag.
This makes me wonder if I was correct in my notion that we do not use an article when talking about God in sentences like the one above, and in other sentences like for example:
Ich habe eine Frage, die Gott betrifft.
Lass uns über Gott reden.
Nur Gott weiß, was hier geschehen ist.
Keiner steht über Gott.
A search on Google did not reveal many result where people used an article in similar sentences. Are there any rules, or reasons why the article is usually not used here? When is using an article allowed?