Knights hold the energy of the suit. They move that energy, the action characters that embody the extremes of the suit's power. Knights in the traditional court give their life for service to their cause, so they believe in their cause. In this case, their cause is their suit. They are the court cards that aren't sitting in wait, or ruling from a throne--they are on the battlefield, protectors, or the messengers of the court. He does the hard work of the suit. And embodies the entire spectrum of the suits attributes from best to middling to worst.
The Knight of Pentacles appears as a man on a Black Steed bearing a pentacle. He is not launching into battle like the Knight of Swords. He comes steadily. Pentacles, for a little refresher, hold the energy of the element of Earth. They are concerned with issues of finances, career, home, money, and marriage. Material things. This Knight embodies the stable, practical, dependable, hardworking aspects of the Pentacles at their best. He achieves goals. Knights tend to be men or women between the ages of 35 and 50, or so. There is no real limit. The idea here is that the Knights are older than Pages and younger than King. The differences between King and Knight energy is the maturity level and energetic level, I think. Knights are about movement, so this person is out there in the world getting shit done. The Kings have gotten their proverbial shit done, and are now reaping the benefits.
I told you that the Knights represent the best and worst of their suit's energy, and reversed would tend to be the worst of the suits attributes. Those tend to be unethical (so think the ends justifies the means, it is something all Earth signs can wrestle with as practical, utilitarian people.) This reversed knight can be scheming, shrewd (in both positive and negative ways), greedy, stingy or miserly. Or he can be horrible with money and irresponsible. But the attribute would be manifest in a way that affects his home/career/family. So this irresponsibility might come out by coming into work late, leaving early, stealing company products, embezzlement, rather than blowing off friends for a drink. Does that make sense?
Knights of Pentacles, as all court cards do, tend to represent people in our lives. They can be validations in a reading about who Spirit means. So Pentacles are earth signs--Taurus, Virgo or Capricorns. They tend to be dark-haired, serious, honest, not overly emotional, but thoughtful and considerate. They tend to have dry senses of humor. They are loyal.
If you have any questions, post it below.