Below is some information that was forwarded to me about John Jack:

"Last week I was visiting in Concord, Mass. and saw John Jacks' tombstone in the original city cemetary. John Jack was a former slave who had been owned by shoemaker Benjamin Barron of Concord, MA. Jack was able to buy his freedom and before his death on March 17, 1773. According to the local historian his epitaph was written by a local attorney who was an active abolitionist.

This attorney was also a Torrey and supported the British during the Revolutionary War. He had to flee for his life since Concord was a hot bed of British resistance. No one ever knew for sure where he went.

Here's the tombstone epitaph he wrote:

God wills us free
Man wills us slaves
Gods will be done
Here lies the body of John Jack,
Native of Africa. Who died March 1773
Aged about sixty years
Tho' born in a land of slaves
He was born free
Tho' he lived in a land of liberty
He lived a slave,
Till by his honest tho' stolen labour
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 put him on a footing with kings
Tho' a slave to vice
He practiced those virtues
Without which kings are but slaves. "