What beast was’t, then,
That made you break this enterprise to me?
When you durst do it, then you were a man;
And, to be more than what you were, you would
Be so much more the man. Nor time nor place
Did then adhere, and yet you would make both:
They have made themselves, and that their fitness now
Does unmake you. I have given suck, and know
How tender ’tis to love the babe that milks me:
I would, while it was smiling in my face,
Have pluck’d my nipple from his boneless gums,
And dash’d the brains out, had I so sworn as you
Have done to this.

This is said by Lady Macbeth as she try’s to make Macbeth realize how serious she is about killing the king.