It is the cave in the field of Machpelah, near Mamre in the land of Canaan, which Abraham bought for a burial plot from Ephron the Hittite.
So Abraham secured the field and the cave that was in it as a burial site from the sons of Heth.
Then Abraham got up from mourning his dead wife and said to the sons of Heth,
“I am a temporary settler among you. Grant me ownership of a burial site among you so that I may bury my dead.”
His sons Isaac and Ishmael buried him in the cave of Machpelah near Mamre, in the field of Ephron the son of Zohar, the Hethite.