What rhetorical devices does Shylock use?
The device used in this passage is the rhetorical question. Shylock draws his persecutors' attention to the humanity of the Jewish race by prompting them to see the common humanity shared between Christian and Jew.
Another device used in the passage is grammatical parallelism. The structure of Shylock's sentences share a similar pattern:
Hath not a Jew eyes. . .
Hath not a Jew hands. . .
If you prick. . .
If you tickle. . .
If you poison. . .
This parallelism sets the ground for the other rhetorical device of repetition. The repeated use of introductory conditional clauses emphasizes emphasizes Shylock's point that there is no difference between the two races, that both share the same humanity.
Finally, the rhetorical device of the catalog is employed in the listing of items grouped by type: bodily appearance, bodily needs, bodily vulnerabilities. The device of repetition is seen also in the emphasis on the body.
Shylock's rhetoric is displayed most prominently in his famous monologue, known commonly by the phrase, "If you prick us, do we not bleed?" The speech can be found in the first scene of the third act.
The rhetoric of this passage appeals to the common humanity of men, suggesting that the distinctions of class and race are superficial in comparison with the underlying common nature shared by all.
Shylock does not claim common humanity to argue for more enlightened relations, however. Instead, he uses the proposition to argue his just right to revenge.
This passage has several parts: (1) catalog of abuses, (2) meditation on a common humanity, (3) meditation on common responses to injustice.
These three division unite to conclude with the following proposition:
"The villainy you teach me, I will execute, and it shall go hard but I will better the instruction."
Shylock's rhetorical point is that cruelty begets cruelty.