In the beginning of Act IV sc.1 Macbeth addresses the witches arrogantly and commands them to tell him what mysterious activities they are engaged in:
In Act I sc.3, however, when he first meets the witches his attitude towards them is one of shock and surprise at seeing such weird creatures and asks them:
In the opening scene, the witches proposed to meet Macbeth on the heath & so they met him in act1 sc.3. In act4 sc.1, it is Macbeth who goes to the witches' cavern to seek further information & support. When the witches first met Macbeth, it was their urge to lay the trap. Now irrevocably caught in the trap, Macbeth feels the urge to meet the witches.
Macbeth addresses the witches now in a tone of sarcastic proximity:
" How now, you secret, black, and midnight hags!
What is 't you do? "
By now, Macbeth has come a long way in his bloody career & there is no question of going back. When the witches first met him & made their proclamations, he was surprised & confused. But now he is more seasoned and more desperate; he has come himself to seek the 'supernatural soliciting' which, he knows, is evil. Macbeth now sounds more commanding & more determined. He is 'bent to know,/By the worst means the worst'. Working as an agent of evil, Macbeth seems to have gained a sense of mastery over the messengers of Hecate:
" I conjure you, by that which you profess,
Howe'er you come to know it, answer me:
Though you untie the winds and let them fight
Against the churches; though the yesty waves
Confound and swallow navigation up;
Though bladed corn be lodg'd and trees blown
Though castles topple on their warders' heads:
Though palaces and pyramids do slope
Their heads to their foundations; though the
Of Nature's germens tumble all together,
Even till destruction sicken; answer me
To what I ask you."