זוהר בראשית — דף רלב ע”ב

The cave is called Makhpelah because it is doubled - the Garden of Eden below corresponding to the Garden of Eden above. The patriarchs correspond to the great nations of the world. When they were buried there, all the worlds became connected. And this place is preserved until the day when the dead will rise. The cave of Makhpelah is the secret of resurrection and the future redemption.