When Sarah was 127 years old,
she died at Kiriath-arba (now called Hebron) in the land of Canaan. There Abraham mourned and wept for her.
Then, leaving her body, he went to the Hittite elders and said,
"Here I am, a stranger in a foreign land, with no place to bury my wife. Please let me have a piece of land for a burial plot."
The Hittites replied to Abraham,
"Certainly, for you are an honored prince among us. It will be a privilege to have you choose the finest of our tombs so you can bury her there."
Then Abraham bowed low before them and said,
"Since this is how you feel, be so kind as to ask Ephron son of Zohar
to let me have the cave of Machpelah, down at the end of his field. I want to pay the full price, of course, whatever is publicly agreed upon, so I may have a permanent burial place for my family."
Ephron was sitting there among the others, and he answered Abraham as the others listened, speaking publicly before all the elders of the town.
"No, sir," he said to Abraham, "please listen to me. I will give you the cave and the field. Here in the presence of my people, I give it to you. Go and bury your dead."
Abraham bowed again to the people of the land,
and he replied to Ephron as everyone listened. "No, listen to me," he insisted. "I will buy it from you. Let me pay the full price for the field so I can bury my dead there."
"Well," Ephron answered
"the land is worth four hundred pieces of silver, but what is that between friends? Go ahead and bury your dead."
References for Genesis 23:15
So Abraham paid Ephron the amount he had suggested, four hundred pieces of silver, as was publicly agreed.
He bought the plot of land belonging to Ephron at Machpelah, near Mamre. This included the field, the cave that was in it, and all the trees nearby.
They became Abraham's permanent possession by the agreement made in the presence of the Hittite elders at the city gate.
So Abraham buried Sarah there in Canaan, in the cave of Machpelah, near Mamre, which is at Hebron
The field and the cave were sold to Abraham by the Hittites as a permanent burial place.