Epigraph to a Grave in Concord, Massachusetts

God wills us free; man wills us slaves.
I will as God wills; God's will be done.

Here lies the body of
JOHN JACK
a native of Africa who died
March 1773, aged about 60 years.

Tho' born in a land of slavery,
He was born free.
Tho' he lived in a land of liberty,
He lived a slave.
Till by his honest, tho' stolen labors,
He acquired the source of slavery,
Which gave him his freedom;
Tho' not long before
Death, the grand tyrant
Gave him his final emancipation,
And set him on a footing with kings.
Tho' a slave to vice,
He practised those virtues
Without which kings are but slaves.

The epigraph above is on a Concord gravestone.  Historian Michael Kammen (my graduate school advisor), notes in his 1972 book People of Paradox that "[i]n the nineteenth century this became the most famous epitaph in America, and was reprinted in English, French, German and Scandinavian newspapers." (p. 193)

The current gravestone is a facsimile of the original; the present copy was erected in 1830.  Here's the picture of the grave from Alfred Sereno Hudson's 1904 book The History of Concord, Massachusetts, Volume 1: Colonial Concord:

And here's the best contemporary picture I could find of the gravestone:

Image source here (click the above photo for a larger, almost-legible version).  Alternate images here, here, here, here and here.

There is a 1902 essay about John Jack, and about Daniel Bliss (the loyalist lawyer who wrote Jack's epigraph) here, online as a free google book.  The grave is on find a grave here.  H/T to Jonathan Holloway for putting me on this trail.