Deleting something from your MereChurch is straightforward, but you'll want to make sure that it's not being referenced anywhere. Gospel.io protects you from deleting documents that are used elsewhere on the site, which saves your visitors from dead links!
To delete a document, select the menu to the right of your 'Publish' button, like so:

Before you delete the post, Gospel.io will let you know if it's being referenced anywhere else on your site:

You can force this Document to delete anyways, or go take care of those references and then delete the document.