According to Machiavelli, "The choosing of ministers is a matter of no little importance for a prince." Nonetheless, the value of a prince's advisors ultimately depends on the wisdom of the prince himself. Machiavelli writes that the first impression of a ruler's intelligence is based on the "quality" of the men that he chooses to advise him. If his ministers are "competent and loyal," then a prince is considered wise, since he has been intelligent enough to recognize these men's abilities and skillful enough to retain their loyalty. If a prince's advisors are not competent and loyal, then the prince himself is considered deficient.
Observers judge a prince's intelligence on the basis of his ministers' abilities and qualities. A prince must be skilled and intelligent himself in order to profit from the advice of able ministers. A ruler who lacks prowess and wisdom will not derive any benefit from even the most competent advisors. Skilled and loyal ministers are extraordinary assets, but if the prince who employs them lacks wisdom, then their usefulness is lost.
Citing the modern Italian example of the prince of Siena and his skilled chief minister, Machiavelli explains that three types of intelligence exist: "One kind understands things for itself, the second appreciates what others can understand, [and] the third understands neither for itself nor through others." Machiavelli continues, "This first kind is excellent, the second good, and the third kind useless." Machiavelli states that even if a prince "has no acumen [i.e., wisdom] himself," he must possess "the discernment to recognize the good or bad" in the actions of his ministers. In that way, a prince can "praise or correct [his advisors' actions] accordingly" and guard himself against the deceptions and schemes of corrupt ministers.
At the very least, an able prince must possess either wisdom of his own or the ability to assess capably the advice and actions of his ministers. A ruler who possesses neither wisdom nor this skill of discernment will quickly come to ruin. The ability to manage one's advisors forms a key aspect of prowess. A prince must have the intelligence to guide his ministers and the demonstrable prowess to guard against scheming ministers. If not, then power-hungry advisors will exploit a ruler's weakness.
Machiavelli offers advice for princes seeking to assess their ministers. If a minister thinks only of himself and chases "his own profit in everything he does," then he will prove inadequate in his service to a prince. Machiavelli declares, "A man entrusted with the task of government must never think of himself but of the prince." For his part, a prince must attempt "to keep his minister up to the mark" by being "considerate towards him," paying him honor, and sharing with him "both honors and responsibilities." A ruler must strive to make his ministers dependent on his benevolence and ensure that they remain in his debt. If a minister feels sufficiently valued and compensated, then he will "fear changes" and become less likely to betray his employer.
To ably serve the prince, a minister must place the wellbeing of the state and his employer before his own interests. In return, a prince must reward his able ministers with "honors and responsibilities," which convey a ruler's trust. By displaying trust, a ruler earns his ministers' goodwill and ensures their loyalty. As with the masses, a prince must manage his relationship with his advisors so that they remain dependent on the continuance of his rule. In this way, their goodwill guards against conspiracy.
Machiavelli summarizes, "When .... relations between princes and their ministers are of this kind, they can have confidence in each other." If not, then a ruler and his ministers will distrust one another, ending in disaster for one side or the other.
Mutual trust lays the essential foundation for a stable relationship between a prince and his ministers. Without trust there cannot be the goodwill that deters conspiracy.