What does Obadiah 1:10 mean?

The first recorded murder in the Bible is that of Abel, killed by his brother Cain (Genesis 4:8–16). Violence is immoral; violence against one's family is even worse. The nations of Edom and Israel were descended from two brothers. Esau's descendants became the Edomites, Jacob's became the Israelites. Over the centuries, Edom continued to torment Israel. Instead of acting as a "brother" nation, they acted as their enemies. Even when Israel was fleeing Egypt, Edom persecuted them (Numbers 20:20–21).

The worst example of this occurred just before the writing of Obadiah's prophecy. When Israel was attacked by Babylon in 587 BC, Edom did not step in to help. At first, they simply sat by and watched. Then, they helped to capture fleeing refugees and participated in the looting of Jerusalem.

This verse prophesies both shame and ruin for Edom. The ruin would eventually come when Edom was routed and driven from their homes. What was left of Esau's nation was eventually obliterated by the Roman Empire. The shame came in how that destruction occurred: overconfident Edom was ambushed by their own allies. The "wisdom" of Edom failed to protect them from attack.