What are examples of literary devices as well as their effect on the audience in act 3 scene 1 of Macbeth?

First, Shakespeare gives us two soliloquies almost back-to-back: Banquo's secretive musings on the Weird Sisters' prophecies, which start the scene in an eerie, hushed manner, then shortly thereafter, Macbeth's "To be thus is nothing" soliloquy, which reinforces these musings but from another viewpoint. Macbeth's speech foreshadows the death of Banquo. Also used is repetition, in "To make them kings, the seed of Banquo, kings!" which emphasizes Macbeth's agitated state of mind and conjures up further unease in the audience.
When speaking to the murderers, Macbeth uses sarcasm to inflame the killers toward their purpose ("Are you so gospell'd / To pray for this good man and for his issue"), and also compares the murderers, if they fail to rise to his bait, to various kinds of dogs.
In a device that Shakespeare frequently uses to "punch" the end of important speeches or scenes, this scene concludes with a rhymed couplet, serving to increase the audience's sense of the inevitability of evil and doom that impends.