Soliloquy- A person alone on stage speaking whats on his mind
"I have no spur/
To prick the sides of my intent, but only/
This reason Macbeth is killing Duncan is selfish. He wants to kill Duncan so that he can be king it's not for any ones good but his. Duncan is a loved king he does things for the good of others There is no other reason for Macbeth to want kill him just for his own selfish reasons.