During the days of the Messiah or the reign of King Solomon, a firm foundation of justice and righteous leadership will bring absolute peace to every area of life. This reality is reflected through nature itself, where even the most empty and distant landscapes transform into sources of blessing. On a political and security level, the mountains represent foreign nations and far-off regions [רד״ק, אבן עזרא]. Instead of hiding ambushes or serving as the starting point for wars, these heights will deliver messages of peace, completely removing the fear of conflict [ביאור שטיינזלץ].
On a social and economic level, the primary approach among commentators is that this peace takes the form of agricultural wealth. The land will grow massive amounts of grain and fruit, and this physical plenty will create internal harmony among people. When there is economic plenty and no poverty, jealousy fades away. The daily struggle to survive disappears, and people no longer take advantage of one another. Having enough to eat creates true brotherhood, leading individuals to invite their neighbors to sit quietly under their vines and fig trees.
This profound peace relies on a clear foundation. Some explain that nature will yield its blessings as a direct result of good deeds, the fear of God, and the fair justice maintained by the people and their judges [רש״י, אבן עזרא, מצודת דוד, מלבי״ם]. Others view this righteousness as simply another word for peace itself [אבן עזרא], or as a sign that God's own salvation and justice will crown the natural world [ביאור שטיינזלץ, אלשיך]. Beyond the physical landscape, a deep symbolic meaning exists. The mountains hint at the forefathers of the nation, while the hills represent the mothers. The merit of the fathers works to bring unity and peace to the people, while the merit of the mothers inspires the nation to connect closely with the Divine Presence [חומת אנך].