If someone says to you, "You are a thief" you may be very displeased. It's because everybody knows a thief has a fault in behavior and it is a sin to take the property of another without securing the right or obtaining permission. So, let's look back on ourselves. Have you not used or taken your friend's property without his permission? Did you just assume that because you are very close friends and the item is not expensive that it was OK? No, this is not using the right yardstick as the measure! If we use or take another's possessions without permission, no matter how minor its value is and no matter how close you are as a friend of the owner, it is stealing in God's sight.