The first man's struggle illustrates his lack of virtue, that is he lacks the habitual disposition to give others their just due with ease. A virtue is more than doing the right thing, it is the power to do the right thing with the right attitude, with ease and joy. Thus the second man's ease and lack of struggle display the inherent power of virtue. Virtue's are so potent that they can give us a second nature, an inclination to do good. This inclination is a key mark of virtue, whereas the first man was inclined to take the money, the virtuous man is inclined in the other direction.
Virtues create a gravity towards the good.
The acquisition of virtues is not easy. To be virtuous is an achievement. One cannot become a sailor in a day. Anything that requires skill, be it piloting a plan, playing a concert piano, or pitching a no-hitter, takes arduous effort. So too does the moral life.