From this moment
The very firstlings of my heart shall be
The firstlings of my hand.
– William Shakespeare
Macbeth, Act 4, Scene 1. An enraged Macbeth says this after seeing the apparitions conjured up by the Witches, including a vision of eight kings who are descendants of Banquo. He determines that from this moment he will straight away act on whatever his heart wishes. The once noble warrior is now committed to whatever evil actions serve his purpose.