When you create content, you always need to make sure that you create quality and that you always write original content. Google penalizes websites that use any content that has been plagiarized from other sources and this is one of the main reasons why you need to be careful not to use anything from other sites.
If you are delegating content work to other people, you should be using plagiarism checkers to make sure the work is unique. The best one is Copyscape and it’s a premium service that gives you excellent results for a very low cost. You can check hundreds of articles for as little as $10.