What is the difference between blog post and guest post?

Blog Post is to post an article on your own Blog.
In Guest Post, a webmaster post an article on other bloggers' blog with prior permission.

posting a content on our own blog is known as blog post. Sending a content to post on another blog is known as guest blog.

Guest Blogging is more than writing a blog post for some other blog, it has got many benefits, which can improve your image as a blogger and also help you promote your own blog by reaching out to communities established by these blogs.

Blog Post is a technique to post a blog or any article in a Blog. In Guest Posting, you have to take permission to submit your blog or article from a blog site's webmaster.