My favourite knife is my Leatherman. Why? It’s REALLY sharp. (I’ve even cut cable with it). Second is my chef’s knife. Why? It’s balanced and REALLY sharp – except when it’s blunt. (Then it’s just a pain to use and REALLY dangerous too).
Proverbs 27:17 (http://bit.ly/2GrREj6) says “As iron sharpens iron, so one person (a friend) sharpens another”. This doesn’t mean rubbing each other up the wrong way. It means giving each other the right to be in each other’s business in an up-close and personal way with the intent to make each other better – sharp, balanced and becoming more like Jesus.