In these conflicts of the mind lady Macbeth found her husband, inclining to the better part, and resolving to proceed no further. But she being a woman not easily shaken from her evil purpose, began to pour in at his ears words which infused a portion of her own spirit into his mind, assigning reason upon reason why he should not shrink from what he had undertaken; how easy the deed was; how soon it would be over; and how the action of one short night would give to all their nights and days to come sovereign sway and royalty! Then she threw contempt on his change of purpose, and accused him of fickleness and cowardice; and declared that she had given suck, and knew how tender it was to love the babe that milked her, but she would, while it was smiling in her face, have plucked it from her breast, and dashed its brains out, if she had so sworn to do it, as he had sworn to perform that murder. Then she added, how practicable it was to lay the guilt of the deed upon the drunken sleepy grooms. And with the valour of her tongue she so chastised his sluggish resolutions, that he once more summoned up courage to the bloody business.
So, taking the dagger in his hand, he softly stole in the dark to the room where Duncan lay; and as he went, he thought he saw another dagger in the air, with the handle towards him, and on the blade and at the point of it drops of blood: but when he tried to grasp at it, it was nothing but air, a mere phantasm proceeding from his own hot and oppressed brain and the business he had in hand.
Getting rid of this fear, he entered the king's room, whom he dispatched with one stroke of his dagger. Just as he had done the murder, one of the grooms, who slept in the chamber, laughed in his sleep, and the other cried "Murder," which woke them both: but they said a short prayer; one of them said, "God bless us!" and the other answered "Amen;" and addressed themselves to sleep again. Macbeth, who stood listening to them, tried to say "Amen," when the fellow said "God bless us!" but, though he had most need of a blessing, the word stuck in his throat, and he could not pronounce it.
Again he thought he heard a voice which cried, "Sleep no more: Macbeth doth murder sleep, the innocent sleep, that nourishes life." Still it cried, "Sleep no more," to all the house. "Glamis hath murdered sleep, and therefore Cawdor shall sleep no more, Macbeth shall sleep no more."