Depends on the country. For the United States, you need appropriate permission or license from the author.
My non-legal rule of thumb is that if you make it 100% clear at the top of the article that this content is from Joanna Smith at xyz.com, and provide a link to the original, then they may be okay with you using it. When it comes to attribution, be generous as it can go a long way. If it is a regular thing your doing from the same source, perhaps ask for permission and what they expect for you to be able to do it. They may give you permission if attribution drives a bit of traffic.
Now, if they challenged you with a cease and desist, would this attribution stand up in court? Certainly not. You’re like a competitor inflicting financial harm, taking the entire piece of content, not transforming it whatsoever, and for the exact same purpose as them. So if they say take it down, then take it down immediately.
Better to write your own content and sample minimally.