You do not have to astonish anyone with your knowledge, but if you want to grow good thoughts, you must fill your mind with truth. Every day you have the chance to put truth into your mind. You study, read, talk, listen, pray, play, watch, and so on. We often need to test what goes into our minds. Not everything is pleasing to God.
Some books are sinful, some pictures are ugly, some conversations are bad.
If something seems wrong, then stop. Don t fill your mind with it. Turn off the television, close the book, walk away from the conversation. Ask your parents if you are not sure. False information, confusion, angry and mean thoughts can clutter up our minds.