I think it was thus the poet wrote, but that such was effaced and then 'of' transposed on account of the metre.
Sc. 2.
"You have taken up
Under the counterfeited zeal of God,
The subjects of his substitute, my father."
I would read seal, in which I am supported by Sidney Walker and Collier's folio. In iv. 1 we have
"That you should seal this lawless bloody book
Of forged rebellion with a seal divine."