A selection of verses relating to the promises given to Esau.

Esau's father Isaac promises him a fertile land:

Genesis 27 verse 39
39 Isaac his father answered him,
“Behold, your dwelling will be of the fatness of the earth,
and of the dew of the sky from above.

The promise is fulfilled. Esau becomes the father of the Edomites:

Genesis 36 verses 6 - 9
6 Esau took his wives, his sons, his daughters, and all the members of his household, with his livestock, all his animals, and all his possessions, which he had gathered in the land of Canaan, and went into a land away from his brother Jacob. 7 For their substance was too great for them to dwell together, and the land of their travels couldn’t bear them because of their livestock. 8 Esau lived in the hill country of Seir. Esau is Edom.
9 This is the history of the generations of Esau the father of the Edomites in the hill country of Seir:

God tells Moses that he has given Esau Mount Seir as his possession:

Deuteronomy 2 verse 5
5 Don’t contend with them; for I will not give you any of their land, no, not so much as for the sole of the foot to tread on, because I have given Mount Seir to Esau for a possession.

God tells the people in Joshua's time that he's given Mt Seir to Esau:

Joshua 24 verse 4
4 I gave to Isaac Jacob and Esau: and I gave to Esau Mount Seir, to possess it. Jacob and his children went down into Egypt.