All scholarly sources are good; not all good sources are scholarly.
A New York Times article or government statistics are (probably) great, wonderful, reliable sources, full of credibility and accuracy and just the kinds of information you should trust.
They are not, however, "scholarly."
Scholarly is a very specific type of good, credible, reliable information source.
Scholarly sources are written by formally trained and educated experts in a field. They tend to provide an in-depth look at a very specific topic (as opposed to an overview or summary) and always have lots of sources cited to back them up. They are published by professional or academic organizations.
Some even go through a peer-review process before publication, through which other experts critically evaluate the content and evidence of an article.
Video created by North Carolina State University Libraries
Used by permission of the Creative Commons License.