Why did Obadiah prophesy against Edom/Esau?

Obadiah 1:8: “In that day,” declares the Lord, “will I not destroy the wise men of Edom, those of understanding in the mountains of Esau?”

‘Edom’ comes from the Semetic word meaning ‘red’, which could refer to the rocks of the region where they lived beside the Dead Sea, or the colour of Esau at birth (Genesis 25:25).

The Edomites were descended from Esau, the twin brother of Jacob (Israel). Although the people were related and should have been at peace, there was considerable enmity between the Israelites and the Edomites. For example, the Edomites would not allow the Israelites to pass through their land as they fled Egypt to the Promised Land (Numbers 20:14-20), and biblical texts also indicate that Edom played a part in the Babylonian destruction of Judah and Jerusalem (Obadiah 1:10-14). These actions probably explain why Obadiah and other prophets spoke such harsh words against Edom.