I followed the priest back to the Abandoned House and down to the altar. He's trapped by Molag Bal and he tell me to make the priest submit. I hit him with the rusty mace until he kneels down then I get no more direction as to what to do. If I hit the priest some more he gets knocked out of the altar trap. No matter how much I wale on him, he just gets knocked to the ground and then gets back up and tries to get back into the trapped altar area.
I've tried reloading a previous save, going out of the house completely then back in and nothing works. Does anyone know of a solution for this?
BTW, I did a search of the forums and didn't find any answer for my problem.
Thanks for any help!

Do you hit him until he's dead? You're supposed to keep hitting him until he dies/all his health is gone. Then he's brought back to life and you do it again. Also, you don't have to use the mace to do it. If you have a weapon that's better you can use that instead.

I know this probably didn't help much but good luck.

I'm guessing you tried hitting from a different 'side'? I seem to remember knocking him out of the cage on my 2nd playthrough, but I walked around to a different side and continued hitting him. You said you left the house and re-entered? That's odd because I couldn't leave...unless you're talking about leaving the house at a different time.

Yeah, that "house doesn't fire" glitch happens sometimes. In my case, I walked in and it was normal and nothing happened, so I just left. Outside? It was the damn Apocalypse. Ground shaking, things flying around, sky is red..

I wish I'd have saved that, in hindsight.