Nor things which are but one, can disunite.
You'are twice inseparable, great, and one.
In this it will be seen that the clause 'Since separation ... can disunite' is attached to the previous verb. It gives the reason why they should 'go to an unseparable union'. In that which I have adopted, which is that of several good MSS., the clause 'Since separation ... can disunite' goes with what follows, explains 'You are twice inseparable, great, and one.' This is obviously right. My attention was first called to this emendation by the punctuation of the Grolier Club editor, who changes the comma after 'goe' (l. 46) to a semicolon.
l. 46. To an unseparable union growe. I have adopted 'growe' from the MSS. in place of 'goe' from the editions. The former are unanimous with the strange exception of Lec. This MS., which in several respects seems to be most like that from which 1633 was printed, varies here from its fellows D and H49, probably for the same reason that the editor of 1633 did, because he did not quite understand the phrase 'growe to' as used here, and 'goe' follows later. But it is unlikely that 'goe' would have been changed to 'growe', and
To an unseparable union growe
is, I think, preferable, because (1) both the words used in l. 44 are thus echoed.
Meeting Another, growes the same,
So meet thy Fredericke, and so
To an unseparable union growe.
(2) 'To an unseparable union growe', meaning 'Become inseparably incorporated with one another', is a slightly violent but not unnatural application of the phrase 'grow to' so common in Elizabethan English: