Leadership requires the development of balance. Balance is the root of justice and enlightenment and requires discipline to maintain one's bearing and to avoid reacting rather than understanding. While in emergency services, one could take that statement as a call to be strong in the face of adverse conditions. However, it is much deeper than that.
Chogyam Trungpa Rinpoche said that:
In the practice of yoga and also within the martial arts, one’s strength or power comes from the development of a balanced state of mind. One is going back or returning to the origin of the strength that exists within oneself. This kind of strength is known as strength in its own right, the strength of fearlessness. To be without fear is to have great strength.
Rinpoche Trungpa was likely teaching us that leaders must sometimes call upon their inner strength to make hard decisions, decisions that may not be popular, but are for the right reasons. We must not fear making decisions for the good of others and we certainly must, if we intend to be good leaders, insist that those we lead do the same without having to fear.
Build strength in those you lead by negating fear; support your subordinates and foster trust, so that they will use ethical and logical decisions to do their jobs. Being balanced creates that strength.