If you republish on your site, use the rel=canonical tag to let search engines know that the article on your main site is the original:

<link href="http://www.example.com/canonical-version-of-page/" rel="canonical" />

You can also read this for more info:
Duplicate Content - SEO Best Practices - Moz

You will not as long as you add Rel="Canonical"

You won't be penalized for adding them to your site.

hey, you can getting many different type of information using telephone system.

You wont be penalized but you have to mention the source of the site where it has been published before.

How will Google know that you are the owner of this content? So you have to use rel=canonical to avoid penalty. If you are still confused, I would recommend you to write a completely new content.

Just to be clear on a very SPECIFIC point that is not being stated here about the rel=canonical tag. It does not work if you are using it and referencing content that is NOT on the SAME site. This command is to prevent duplicate content that is on the same site. Wordpress is notorious for creating multiple URLs for the same content when users create tags and categories, etc... Canonical was created specifically for preventing penalties when a single site has multiple urls created by the CMS.

If you posted the article elsewhere on a different domain, Google will give credit to that site as the original content source. YOU will get penalized (or ignored for ranking) by Google if you take that content and add it to your site word for word. If you try to add the canonical tag to your post, it won't matter because Google will say that you have no right to claim that it is your content since they really can't verify it and since it was on the other site first, they should be credited as the owner.

Try to think of it from Google's perspective. If you could use the rel=canonical tag anywhere and claim original authorship just by adding it to your site, blackhat SEO's would be using it all over the web and stealing credit for stuff from main high page rank pages all over the web that they never created.

Your best bet is to definitely re-write the content as original to your site.

Hope this makes sense.

you won't be if you use Rel="canonical"

Rewrite it atleast, you will get the penalty sooner or later. Why take risk of your money site?

This is a terrible idea to do. Don't use rel=canonical" it doesn't work in 80% of the instances I've tested on. If you want the content on your site for readers, then just post it and set the page to noindex so people can still read it.