Proverbs 27:17 (Message Bible) You use steel to sharpen steel, and one friend sharpens another.
Our focus text points out that one friend sharpens another. To better explain this text, is the friend(s) that you hang around whose behavior is good/bad, in due time you will begin to pick up their ways. Take care to pay attention to the things that you begin to do when you are in your friends company. If you begin to do something that is not good, you need to change whom you hang with, until you are strong enough to sharpen them, instead of them sharpening you.