The Knight of Swords is logical, witty, analytical, just, but he can also be impatient, judgmental, ruthless and verbally aggressive. The Three of Pentacles is a card of planning, hard work, growth and teamwork. It's a grounding, expanding and stable card that provides strong foundation for any type of project, be it professional or personal. The combination of the Knight of Swords and the Three of Pentacles points to either disruptions or fast developments that happen in a team/group of people.
To understand the elemental relationships between the cards, we should always take into account their actual meaning. The elements of the cards are Air (Knight of Swords) and Earth (Three of Pentacles). A neutral combination in which the Earth card often tries to oppose the Air Card by absorbing its energy, through a gravitational pull. However, in this combination, there is an energy that both cards have in common that's the strong desire to achieve something. For that reason, we should expect significant developments in a short period of time.