As the only species of all God’s children bestowed with a rational mind, humanity – according to Dante – is obligated to properly use its God-given gift responsibly. Dante calls this duty the "good of the intellect." All man’s works then should in some way be devoted to honoring nature or worshipping God. Indeed, Dante’s poem could be viewed as such a work, stemming from his own philosophy. Any works that deny God’s infallibility, pervert nature’s trends, or attempt to surpass man’s limits, are sinful. Man’s use of language is particularly subject to this "good of the intellect" ethos, since language is one of the primary expressions of man’s mind.
Because fraud involves a deliberate misuse of man’s mind, it is considered the wickedest of sins.
Despite Brunetto’s generous character and Dante’s warm reaction to him, Brunetto makes a potentially dangerous assertion that man’s only chance at immortality is through the survival of his works; this inherently denies man’s immortal soul.