Character Role Analysis
We think that Virgil’s line, "I shall guide you," is telling. But if you want a long, detailed account on Virgil’s mentor status, see his "Character Analysis."
Briefly, Virgil does a lot of lecturing and reprimanding and praising in the course of his and Dante’s journey through Hell, and this is his sole function. Besides being a conduit of endless information, Virgil acts as a role model for Dante. He gives his protégé tips on how to behave and speak (harshly) to the sinners.