In Act III, Scene 2 of Twelfth Night, Sir Andrew feels slighted by Olivia, but Sir Toby, who has exploited him for his money, encourages him to continue his suit by suggested a duel against Olivia, an act which displays manliness. Fabian pitches in by saying that Olivia slighted him before Cesario just to arouse his jealousy. But Sir Andrew asks Fabian, "'Slight will you make an ass o' me?"(3.2.9). To which Fabian replies, "I will prove it legitimate, sir, upon the oaths of judgment and reason"(3.2.10). Now, the antecedent of "it" is ambiguous here, eliciting some ironic humor as it appears that Fabian refers to his making an ass of Sir Andrew, which he is trying to refute, actually. In the line cited above, "they" refers to "the oaths of judgment and reason," two qualities that are personified in Sir Toby's line, "And they have been grand-jurymen since before Noah was a sailor."
So, in Sir Toby's line, there is both personification and hyperbole.
- Judgment and Reason are personified as grand-jurymen, those who are
- "...since before Noah was a sailor" is an obvious exaggeration , or hyperbole, since Noah, who built an ark to save his family and many animals from the Flood, was no real sailor.
These overstatements are humorous in reference to the foolish Sir Andrew, who wishes to be taken seriously.