The modern philosopher, Robert Greene cautions to, “be wary of friends, they will betray you more quickly, for they are easier aroused to envy…you have more to fear from friends than from enemies.”
Banquo is envious of Macbeth and desires his fair share of the Witches’ prophecy. After Macbeth is crown’d, Banquo muses, “Thou hast it now, King, Cawdor, Glamis, all, as the Weird Women promised; and, I fear, thou play’dst most foully for’t; yet it was said, It should not stand in thy posterity; but that myself should be the root and father of many kings…may they not be my oracles as well, and set me up in hope?”
Banquo shows concern over Macbeth’s ethics in attaining the crown, yet his focus shifts to himself; he becomes more concerned whether Macbeth’s coronation will aid in the fulfillment of his own regal ascension, or rather his posterity transmuting thereunto; e.g. the fulfillment into regal merchandise.
Banquo takes no action to expose Macbeth and thinks in terms of future gain for his heirs. It isn’t surprising that Banquo is happy that the prophecy has taken shape, for it favors his gain. He stays silent; perhaps he fears altering the fate of the part of the Witches’ prophecy favoring him.
Banquo puts too much trust in Macbeth. Banquo’s lack of concern over his own safety (considering Macbeth murder’d the virtuous King Duncan) seems slightly credulous, and he leaves his trust in the regicidal Macbeth.
Robert Greene writes to, “never put too much trust in friends…” Banquo putting any kind of trust in Macbeth proves a monumental blunder as Macbeth becomes envious of Banquo being set up in hope, and begins to feel fearfully suspicious of Banquo’s motives. Every king wishes for their son(s) to succeed the throne after they reign; Macbeth can’t stand the thought of sacrificing the “vessel of his peace” to make “the seeds of Banquo Kings.” This illustrates how one foul crime leads to another. “Blood will have blood.”
Because Macbeth murder’d the King foully and has no hope of lineal succession, he feels proclivitous to prevent others from enjoying what he never will.
Banquo seems to ignore obvious inferences in the Witches’ prophecy; e.g. if his issue become King, and yet he never does, shouldn’t that tell him to be vigilant of anyone who might want to cut him off. Who else than Banquo, who, other than Lady Macbeth, is exclusively privy to Macbeth’s own regal ambitions.
Banquo puts too much trust into this fleeting despot King of Scotland and fails to use the Witches’ insight. If he would have distanced himself from Macbeth, maybe the fates would have been more kind. This misplaced trust Banquo bestows on Macbeth and the overconfidence [or Pride] he has in himself procures his demise.