Macbeth

To be thus is nothing, But to be safely thus. To be king is nothing unless he’s safe.
Our fears in Banquo stick deep; and in his royalty of nature reigns that which would be fear’d. ‘Tis much he dares; and, to that dauntless temper of his mind, he hath a wisdom that doth guide his valour to act in safety. There is none but the whose being I do fear: and, under him, my Genius is rebuked; as, it is said, Mark Antony’s was by Caesar. Macbeth fears Banquo because he’s afraid that he may say something.
He chid the sisters when first they put the name of king upon me, and bade them speak to him; then prophet-like they hail’d him father to a line of kings: Upon my head they placed a fruitless crown, and put a barren sceptre in my gripe, thence to be wrench’d with an unlineal hand, no son of mine succeeding. Macbeth is angry because he doesn’t have any children to pass on the throne to it will go to Banquo’s sons.
If’t be so for Banquo’s issue have I filed my mind; for them the gracious Duncan have I murder’d; put rancours in the vessel of my peace only for them; and mine eternal jewel given to the common enemy of man, to make them kings, the seed of Banquo kings! Macbeth committed this murder and Banquo will benefit by it-his sons will become king.
Rather than so, come into the list, and champion me to the utterance! He’s going to fight fate.