Genesis 23:17-20

So the field of Ephron in Machpelah, which was to the east of Mamre (Hebron)—the field and the cave which was in it, and all the trees that were in the field and in all its borders around it—were deeded over [legally] to Abraham as his possession in the presence of the Hittites, before all who were entering at the gate of his city. After this, Abraham buried Sarah his wife in the cave of the field of Machpelah to the east of Mamre (that is, Hebron) in the land of Canaan. The field and the cave in it were deeded over to Abraham by the Hittites as a [permanent] possession and burial place.