When the besieging army marched through the wood of Birnam, Malcolm, like a skilful general, instructed his soldiers to hew down every one a bough and bear it before him, by way of concealing the true numbers of his host. This marching of the soldiers with boughs had at a distance the appearance which had frightened the messenger. Thus were the words of the spirit brought to pass, in a sense different from that in which Macbeth had understood them, and one great hold of his confidence was gone.
And now a severe skirmishing took place, in which Macbeth, though feebly supported by those who called themselves his friends, but in reality hated the tyrant and inclined to the party of Malcolm and Macduff, yet fought with the extreme of rage, and valour, cutting to pieces all who were opposed to him, till he came to where Macduff was fighting. Seeing Macduff, and remembering the caution of the spirit who had counselled him to avoid Macduff, above all men, he would have turned, but Macduff, who had been seeking him through the whole fight, opposed his turning, and a fierce contest ensued Macduff giving him many foul reproaches for the murder of his wife and children. Macbeth, whose soul was charged enough with blood of that family already, would still have declined the combat; but Macduff still urged him to it, calling him tyrant, murderer, hell-hound, and villain.
Then Macbeth remembered the words of the spirit, how none of woman born should hurt him; and smiling confidently he said to Macduff, "Thou losest thy labour, Macduff. As easily thou mayest impress the air with thy sword, as make me vulnerable. I bear a charmed life, which must not yield to one of woman born."
"Despair thy charm," said Macduff, "and let that lying spirit whom thou hast served, tell thee, that
