No rack can torture me,
My soul 's at liberty.
Behind this mortal bone
There knits a bolder one You cannot prick with saw,
Nor rend with scymitar.
Two bodies therefore be;
Bind one, and one will flee. The eagle of his nest
No easier divest
And gain the sky,
Than mayest thou, Except thyself may be
Thine enemy;
Captivity is consciousness,
So's liberty.

Time and Eternity, p. 198 - Collected Poems (1993)