Macbeth has been told a  prophecy and he is happy and confused about what they have said. They said until the woods move  to a hill he will be inviserball. And they also told him about mucduff. They said mucduff has fled to England to start a war on Macbeth.

“Time, thou anticipated my dream exploits” I think that this means that Macbeth is going to killed some one in mucduffs’s family.