Genesis 23:16-18

So Abraham agreed to the amount, weighed out the four hundred silver shekels according to the merchant’s standard of weight, and in the presence of the Hittites he gave the money to Ephron. So Ephron’s field of Machpelah, east of Mamre, along with the cave and all the trees within its borders, passed to Abraham as his legal possession. The complete transaction was carried out in the presence of the Hittites—those who sat as elders at the city gates.