Following a series of harsh prophecies directed at Mount Seir, a dramatic shift occurs. The prophetic focus turns away from disaster and instead delivers a contrasting message of deep comfort aimed at the Land of Israel.
The primary approach among commentators is that placing these two messages side by side is completely intentional. The downfall of Edom directly serves as a source of relief and comfort for the nation. The message directed at the mountains of Israel is meant to soothe the land itself and speak directly to its heart. This acts as a powerful counter-response to the Edomite enemy, who had celebrated Israel's defeat and eagerly hoped to take over the high land forever [אברבנאל].