Accounts of virtue start with an explanation of courage. The first reason is that a virtue is a mean between an excess and a defect, and the excess and defect of courage are well known. This makes courage first in the order of our (distinct) understanding. Courage is not first in the order of causality (this falls to prudence) nor is it first in the order of the strength and knowability of the passion it deals with (this falls to temperance) nevertheless, there is a very important qualified way in which courage is the first virtue we need.
Courage is the virtuous response to fear, and all virtues are ways of being a Lord over ones own acts, so courage involves standing toward something fearful as the Lord of ones own action. In concrete terms, this means that we confront the possibility of some evil or failure and see the outcome as dependent on our own action. So considered, courage is the gateway to all the other virtues since we become masters of our own acts most of all when we are forced to fight against or overcome something fearful. Children, for example, can’t be virtuous since they relate to all fears as things that ought to be taken away by their parents.
But though children can’t be virtuous, we’ve all had experience being children, and while not everything about the experience needs to be shed in adulthood (there are some ways in which we always remain as helpless as children and need to be aware of this) nevertheless, virtue requires that sooner or later we relate to the fear of failure and evil as something that is up to us to conquer. One of the chief impediments to courage, and therefore to all virtue, is the desire for the comfort and ease we remember in childhood. The fundamental choice of our moral life is therefore between courage- the virtuous response to fear- and the comfort that consists in avoiding this sort of self determination in the face of fear. So considered, courage is not seen as the virtue between the two extremes of bravado and fear, but the virtue that is opposed to sloth- that is, the vice the rejecting the difficulty or danger involved in determining ones own life in the face of fearful things.
Sloth, like every vice, does not present itself as a vice, and the case for sloth is extremely persuasive and convincing. After all, why should we let people stand face to face with fearful things? isn’t the whole purpose of a society to remove fearful and difficult things as much as possible? How can rulers just stand by and do nothing when their citizens are confronted with fearful and difficult circumstances? What if they fail! The voice of sloth argues, not without force, that courage is nothing other than what a person is stuck having to do because of the laziness and inaction of our superiors- and even the inaction and indifference of God himself. If God isn’t going to come sweeping down and snatch us out of every fearful and terrible circumstance, then we will find a benevolent leader who will! Sloth therefore involves a critique of providence and a call for a benevolent, all powerful leader.