A poster on another thread, the topic of which was questioning the authenticity of the last 12 verses in the book of Mark, wrote that it doesn't really matter because there is no doctrinal teaching in Mark 16:9-20 that cannot be proved elsewhere in agreed Scripture.
I made the mistake of sticking my nose into the discussion by pointing out that actually there is a statement in verse 9, as the KJV and similar versions have it, that is used for a doctrinal teaching that is to be found nowhere else in Scripture. As the KJV translates it, it is the only place that puts the resurrection on the first day of the week. I then suggested that whenever the discussion of seventh day observance versus first day observance comes up, first day proponents usually use the idea of a first day resurrection to justify the change, and when questioned about the day of resurrection, quote Mark 16:9. The poster came back with: "Quote a published author who has done that." - I have not yet been able to come up with one. Does anyone here know of one?