Answer:
comic relief
Step-by-step explanation:
Faustus is addressing these lines to Mephistopheles, a demon, with whom he sold his soul to. A friar is a priest who is known to be a holy person which is the exact opposite of evil. Hence, in the seriousness of the theme of the play, these lines break the tension and give some light humor. How then can the devil, an evil incarnate ever become holy?