What does Genesis 23:18 mean?
The previous verse detailed the property Abraham has purchased from Ephron the Hittite. It is located in Machpelah, east of Mamre. It includes a cave, a field, and all the trees within the boundary of that field. Abraham has purchased this plot in order to make it his family tomb. Sarah has recently passed away (Genesis 23:2), and Abraham intends to bury her there. This act of burial has particular significance in that time period. Choosing to bury one's dead in a specific place was a sign of both residency and ownership. Even though he has to buy it, Abraham is able to take possession, within his lifetime, of a small portion of the Promised Land.All of this small parcel is now "made over" to Abraham as his possession. The transaction is concluded in full view of the Hittites and all who go in at the gate of the city. These are likely the elders of Hebron. This is a public and legal transaction according the customs of the land at this time.