and Lady Macbeth, who has entered a moment before, exclaims,

                  Woe, alas! 
     What, in our house?

his answer,

Too cruel anywhere,

shows, as I have pointed out, repulsion, and we may be pretty sure that he suspects the truth at once.  After a few words to Macduff he remains absolutely silent while the scene is continued for nearly forty lines.  He is watching Macbeth and listening as he tells how he put the chamberlains to death in a frenzy of loyal rage.  At last Banquo appears to have made up his mind.  On Lady Macbeth’s fainting he proposes that they shall all retire, and that they shall afterwards meet,

     And question this most bloody piece of work
     To know it further.  Fears and scruples[235] shake us: 
     In the great hand of God I stand, and thence
     Against the undivulged pretence[236] I fight
     Of treasonous malice.

His solemn language here reminds us of his grave words about ’the instruments of darkness,’ and of his later prayer to the ’merciful powers.’  He is profoundly shocked, full of indignation, and determined to play the part of a brave and honest man.

But he plays no such part.  When next we see him, on the last day of his life, we find that he has yielded to evil.  The Witches and his own ambition have conquered him.  He alone of the lords knew of the prophecies, but he has said nothing of them.  He has acquiesced in Macbeth’s accession, and in the official theory that Duncan’s sons had suborned the chamberlains to murder him.  Doubtless, unlike Macduff, he was present at Scone to see the new king invested.  He has, not formally but in effect, ‘cloven to’ Macbeth’s ‘consent’; he is knit to him by ’a most indissoluble tie’; his advice in council has been ’most grave and prosperous’; he is to be the ‘chief guest’ at that night’s supper.  And his soliloquy tells us why: 

     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.  If there come truth from them—­
     As upon thee, Macbeth, their speeches shine—­
     Why, by the verities on thee made good,
     May they not be my oracles as well,
     And set me up in hope?  But hush! no more.

This ‘hush! no more’ is not the dismissal of ‘cursed thoughts’:  it only means that he hears the trumpets announcing the entrance of the King and Queen.