The rhetorical devices that Thoreau used in Resistance to the civil government are:
Metaphor: is used to help the reader to understand the argument he is trying to say. Government as a machine (mechanical, unnatural, dehumanized).
Anaphora: Thoreau uses repetition and parallel structures. For example, repetition of "Why" or "does not".
Allusion: Christ, Copernicus, Luther, Washington and Franklin rebels.