Commentary Inf IX 118-123

We will eventually be apprised of the heretical nature of the beliefs of the inhabitants of these tombs, whom we can hear but cannot see. We will have a similar experience when we look upon the flames of the false counselors in cantos XXVI and XXVII, also unseen in their flames, yet entirely audible. And see C.Inf.XIX.25, for discussion of the parodic inversion of Pentecostal fire in the punishment of sins that involve the perversion of the gift of the Holy Spirit. One thinks of these heretics, the sodomites (Cantos XV and XVI), and the false counselors. All these three loci contain sinners who use their intelligence in such ways as to beguile others into believing what they should not believe.