“they have neither the tooles, nor skill, nor heart to fence their grounds (p. 95)."
Letter from Eliot to Whitfield, April 18, 1650; Indians of the Nipmuck Country in Southern New England 1630-1750 By Dennis A. Connole
My take on this is that John Eliot was encouraging Indians to turn existing stone rows into the legal fences defined by the early colonists that justified and signified ownership of land. The multi-purpose stone rows that were created by Indians were not only practical devices for land management of resource zones but also contained elements of Ceremonialism, a sacredness and spirituality shown by the careful and artistic placement of the stones, the shapes of the rows themselves, Great Serpent Effigies, sort of as if the whole Ethnographic Cultural Landscape was a big piece of religious architecture, protected by the spirit beings.
The tooles were the metal axes and wedges used to split rails, I'm guessing, the skills the ability to make "cross and rail" fences and the heart similar to a response to the suggestion that your church house would make a good barn for livestock.
"Your sacred stone sweat lodge would be a great pigpen."
(I added the photos on April 22, 2019)