DON"T JUDGE A BOOK BY ITS COVER

DON"T JUDGE A BOOK BY ITS COVER 

means not to judge people or things by what they look like from the outside. People shouldn't be judged by how they look but be judged by their actions. It actually means that people cannot be judged by what they appear like to you at first, it is necessary to get to know them and "read" them before you can judge them It means not to judge people by the way they look or act. Something very powerful can be inside them.

it means don't judge a person on how they look and only judge them on who they really are!

If you judge a book by it's cover is to judge someone or something before you get to know them or try it. Such as if someone looks funny and you don't know them you shouldn't make fun of them because they could turn out to be the nicest person you ever met. Also if someone advertises for a product and you don't think it will work you shouldn't because it might work really good and it will be fun and/or good for you to have. On the other hand something could look good and be really bad. So if someone is really pretty that doesn't mean 'Oh, that person is really pretty they must be nice!' They could be really stuck up and mean. Or if something looks shiny and new and people on TV. say it works really good it could be bad.
It means you don't just look at something (or someone)and judge it (or him) right away.

Ex. You see a book you should maybe do some research or read a little of it. Don't just look at the cover and say "that's a bad book." Same applies with people.