Act 1

Violence:

(1.2.18-24) Which smoked with bloody execution, like valor's minions carved out his passage... and fixed his head upon the battlements.

This quote explains the execution of Macdonwald, and as he puts his head on a stick.

Scene 3... The witches praises the worthy MacBeth for the acts of violence that he shall do in the future.

Scene 5 : MacBeth and Lady MacBeth are thinking of killing the the king because of what the witches told them.