Strength is an important part of leadership because when leading you need to make an impreshion on people so they want to follow you. You want to be strong so you can make not only your self feel better about helping others but make other people feel good because your making an example for them.
It’s quite simple, really. Strength doesn’t always mean how much muscle you have or how physical you can be. Strength can be a matter of character or morals. To be a leader you need to be able to inspire and give those around you a drive to follow you and your example. If you look at any historic leader (regarding religion, countries, etc) they all have one thing in common. They have this strength in their faith of what they believed in.
