Getting new post Content (HTML) from text editor

Hey everyone.
This is my first post here, since it’s the first time i am developing for wordpress.
I am building a plugin, that is using the

publish_post

hook.

I need to capture the contents of the new post created, what is present in the rich text editor.

when i make a die(var_dump($_POST)), i get [‘content’] and [‘post_content’] with the exact same value. That value is close to what i am looking for, but it discards the html formatting.
How can i get the exact HTML that is going to be published by wordpress?

Thanks ??