Fear is when you do not trust God's promises. Fear causes you run and hide or increase Adrenaline that makes you fight. When adrenaline is increased in the body it causes the muscles to tense making muscles stronger/faster. Fear keeps you from dangerous situations. Here is the difference between fear and courage in this situation.
Your friend is pressuring you to go into a random persons' house.
Fear: "I might get caught and arrested."
not afraid: "Okay, nobody is home and the police can't punish me anyway."