Genesis 23:20
And the field, and the cave that is therein, were made sure unto Abraham for a possession of a buryingplace by the sons of Heth. And the field, and the cave that is therein, were made sure unto Abraham for a possession of a buryingplace by the sons of Heth.
The field and the cave secured to Abraham were the cave of Machpelah at Hebron, the burial place of the patriarchs. He bought them from the sons of Heth, the Canaanites, for a burial place. Although God had promised him the whole of Canaan, this purchase was his only landholding in the promised land, for he owned none of it otherwise and did not receive Canaan as his inheritance during his lifetime.
When Sarah died he had not so much as a piece of land in which to put his dead, so he had to buy the field and the cave. The promise was therefore not fulfilled to him in present prosperity in land or possessions. He was satisfied because the Lord opened before him the view of immortal life on this earth purified as his home.
Believers learn from this that they are only pilgrims and strangers in this world, seeking the city which Abraham looked for, whose builder and maker is God. They are not to expect all reward here in possessions, land, gold, or silver. They are instead to hold the claim of future immortal life and to expect an eternal weight of glory.