Genesis 36 is a long list of names, and many readers skip it. But it opens with a key sentence: “Now this is the genealogy of Esau, who is Edom.” Esau moved to the mountains of Seir, south and east of the Dead Sea, because the land could not support both him and Jacob. Edom means red, recalling the red stew and Esau's red appearance at birth. The chapter shows that God kept His word to Isaac: Esau, too, became a nation with chiefs and kings.
In fact, Genesis 36:31 notes that Edom had kings “before any king reigned over the children of Israel.” Esau's line developed faster in worldly power. One of his grandsons was Amalek, whose people later attacked Israel in the wilderness. Teman, another grandson, became a name connected with wisdom; Eliphaz the Temanite, one of Job's friends, may come from this family.
Centuries later the brother nations met again. When Israel came out of Egypt, Moses sent messengers to the king of Edom: “Thus says your brother Israel.” He asked only to pass through on the King's Highway, promising not to drink from their wells without paying. Edom refused and came out against them with a strong army. The brother's door was closed.
Yet God told Israel not to hate Edom. “You shall not abhor an Edomite, for he is your brother.” In Deuteronomy 2 the LORD told Israel not to fight with the sons of Esau, “for I will not give you any of their land… because I have given Mount Seir to Esau as a possession.” God honored His promise to Esau even when Esau's children treated Israel badly.
The prophet Obadiah, the shortest book of the Old Testament, is a word against Edom's pride and cruelty when Jerusalem fell. “For violence against your brother Jacob, shame shall cover you.” Edom stood aloof and rejoiced over Judah's ruin. Obadiah warns, “As you have done, it shall be done to you.” Then he ends with hope: “And the kingdom shall be the LORD's.” In the New Testament, the Herods were of Idumean (Edomite) descent — and the King they opposed was the true King of Israel.