In Patrick Henry's famous speech given in 1775, he uses several literary techniques. He seemed particularly fond of allusions. The first one refers to the Greek mythological sirens, who were said to lure sailors with their beautiful singing voices, to crash into the rocks. From there Circe would turn the survivors into pigs. In Henry's speech, he says,
"We are apt to shut our eyes against a painful truth, and listen to the song of that siren till she transforms us into beasts."
Later in the speech, Henry has an allusion to the Bible when he says, "Suffer not yourselves to be betrayed with a kiss." This refers to Judas betraying Jesus, and Henry uses it here to say that just because Parliament seemed positive about the colonists' petition did not mean that they really were, and that the colonists should beware.
You can find many other literary devices in Patrick Henry's speech. I am attaching a couple of links for you to peruse.