Could be Speakon cables wired "the other way" (there are at least two ways to wire them).
Could be a blown power section.
Does that require a load on it? In other words, are you supposed to run it without a speaker at all?
Do the cabs work at church with another amp?
Are you using the same guitar cable at church?
This really could be any of a dozen things. We need to know EXACTLY what you have narrowed down and what you haven't. Too many variables here so far.
If you're gonna be stupid, you gotta be tough. - My Grandmother