What a fantastic title! I gather this is an excerpt from a letter Lovecraft wrote, recounting a dream he'd had. So, again, it's not a finished short story, though it was published as one after his death in Weird Tales.
The tale is of a narrator who inadvertently, and to be honest rather stupidly, releases the trapped soul and more of the titular clergyman. If you're told not to do anything with a mysterious box, whatever you do, follow those instructions! Though to be fair, if he'd done that, the story would be even shorter, and much less fun.
If it had been published as a story in Lovecraft's time it would definitely have benefited from further development. It's rather sparse in many places, and needs some touches added. But, oh, it's so imaginative, and well conceived as an idea. It's also satisfyingly terrifying, with a good ending. I particularly liked the images of the clergyman moving around, and the other characters that appeared. And the burning of the books. Yes, it's really very evocative.
I think this is probably the Lovecraft fragment that I'd most like to have seen finished properly. I think it's a lovely piece, albeit rarely read by Lovecraft fans, and well worth seeking out.