Condense Stephen's commentary.
One of all, the least of all, is the victim predestined. Once by inadvertence, twice by design he challenges his destiny. It comes when he is abandoned and challenges him reluctant and, as an apparition of hope and youth holds him unresisting. It leads him to a strange habitation, to a secret infidel apartment, and there, implacable, immolates him, consenting.
Why was the host (victim predestined) sad?
He wished that a tale of a deed should be told of a deed not by him should by him not be told. (17.119-120)