John Gill Commentary Genesis 49:32

"the field and the cave that is therein, which was purchased from the children of Heth." — Genesis 49:32 (ASV)

The purchase of the field, and of the cave that is there, was
from the children of Heth .
] Which is repeated for the certainty of it, and that it might be taken notice of, that both the field and cave were bought by Abraham of Ephron the Hittite, and that the children of Heth were witnesses of the bargain, and of the payment of the money, and by whom the estate was made sure to Abraham; all which might be urged, if any controversy should arise about it; see (Genesis 23:16–20)