What do we learn in macbeths soliloquy in scene 1 of act 3?

In Act III, Scene I, Macbeth summons the two murderers he has hired. While he waits for them, he voices his greatest worry of the moment—that the witches' prophecy will also come true for Banquo, making his children kings. He will put an end to such worries by hiring two men to kill Banquo and Fleance.