The minister pounds his fist on the podium when he says the words "sin" and "evil." What function does this form of nonverbal communication serve?

Emphasizing.

Explanation:

There are a variety of verbal or non-verbal communication techniques employed by the authors/speakers to convey their intended idea constructively. As per the given description, the non-verbal communication by 'pounding his fist on the podium' signifies that the speaker (minister) intends to emphasize the idea of 'sin' and 'evil' and convey it productively to each and everyone out there in the audience by grabbing their attention (by pounding fist). His non-verbal communication act as cue for the readers that he intends to convey something significant in the context and thus, they concern their attention towards it and understand it effectively which is the chief goal of the speaker.