That makes his opening with this bigger key:

30 This other doth command a little door

Which from the vineyard to the garden leads;

[There have I made my promise]

Upon the heavy middle of the night

To call upon him.

35 Duke. But shall you on your knowledge find this way?

Isab. I have ta’en a due and wary note upon’t:

With whispering and most guilty diligence,

In [action all of precept], he did show me