If your power is decreasing then

you have to do something about it right away

The measure of a man is what he does with power

At any given moment, you have 

the power to say this is not how the story is going to end

Nearly all men can stand adversity, 

but if you want to test a man's character, give him power

The way to have power is to take it

Power simply has the ability to exercise influence over others.