though I am _well acquainted_ with your quality and rank. [Warburton
explained this as "the critical juncture"] How the _critical juncture_
is the _spy o' the time_ I know not, but I think my own conjecture
right.

III.ii.38 (467,1) nature's copy's not eternal] The _copy_, the _lease_,
by which they hold their lives from nature, has its time of termination
limited.

III.iii.1 (469,6) But who did bid thee join with us?] The meaning of
this abrupt dialogue is this. The _perfect spy_, mentioned by Macbeth in
the foregoing scene, has, before they enter upon the stage, given them
the directions which were promised at the time of their agreement; yet
one of the murderers suborned suspects him of intending to betray them;
the other observes, that, by his exact knowledge of _what they were to
do_, he appears to be employed by Macbeth, and needs not be mistrusted.

III.iv.1 (470,9) You know your own degrees, sit down: at first,/And last
the hearty welcome] As this passage stands [sit down:/At first and
last], not only the numbers are very imperfect, but the sense, if any
can be found, weak and contemptible. The numbers will be improved by
reading,

--_sit down at first,
And last a hearty welcome_.

But for _last_ should then be written _next_. I believe the true reading
is,