It's the Witches Fault
Comic Relief:"Knock, knock, knock! Who’s there, i' th' name of Beelzebub? Here’s a farmer that hanged himself on the expectation of plenty. Come in time, have napkins enough about you, here you’ll sweat for ’t" (Shakespeare Act 2, Scene 3). This is Comic Relief because the Porter is talking about how everyone nowadays is doing bad things that send them to hell right after the scene where Macbeth killed Duncan.
Verbal Irony: "Here we now our country's honor roofed, Were the graced person of our Banquo present, Who may I rather challenge for unkindness Than pity for mischance" (Shakespeare Act 3, Scene 4). This is Verbal Irony because he says he hopes nothing bad has happened to Banquo, even though he had already sent murderers out to kill Banquo and his son Fleance.