The field and the cave in it were acquired from the sons of Heth.”

So Abraham secured the field and the cave that was in it as a burial site from the sons of Heth.

“No, my lord! Hear me out. I sell you both the field and the cave that is in it. In the presence of my people I sell it to you. Bury your dead.”

So Abraham secured Ephron’s field in Machpelah, next to Mamre, including the field, the cave that was in it, and all the trees that were in the field and all around its border,