Our will became the servant to defect
Which else should free have wrought.
i.e., As we were unprepared for Duncan's arrival, our desire to entertain him properly (our will) had to bow down to inadequacy (became the servant to defect). Otherwise, our will would have operated freely and we would have done more.
How to cite this article:
Mabillard, Amanda. Macbeth Glossary. Shakespeare Online. 20 Aug. 2000. (date when you accessed the information) < http://www.shakespeare-online.com/plays/macbeth/macbethglossary/macbeth_2_1/macbethglos_unprepared.html >.