Case studies on Job and the prophets in their Septuagint translations are used to address the question ‘What does sarcasm do?’ – the issue of sarcasm’s pragmatic functions. I hypothesize that sarcasm normally functions as an implicit challenge to what the speaker perceives as a claim to some positive quality made by another party. It is appropriate so long as it is not used against the grain of social hierarchy, although the prophets show a willingness to engage in more subversive uses of sarcasm.