Macebeths state of mind worsens as the last lines say 

“Hear it not duncan, for it is a knell that summons thee heaven to hell”

so what is trying to say in this it shows that Macbeths state of mind the worse that could happen to him and the soliloquy is showing this because it talks of heaven or hell when the sentence says “summons thee heaven to hell” and he thinks that because of how he killed Duncan. As it says hear it not Duncan