A divine promise envisions a completely new reality where sorrow vanishes and joy becomes a permanent state of being. God promises the people of Israel that the days of hearing bad news are over; from now on, they will experience only goodness and happiness [רד״ק, מצודת דוד]. The commands to rejoice are not merely instructions, but powerful guarantees of what the future holds [שד״ל]. This happiness takes two distinct forms. One is an outward display, seen in actions like wearing festive clothes or playing music. The other is a sudden, deep internal joy that fills the heart upon hearing good news [מלבי״ם]. This dual experience is promised to last forever [מצודת ציון], though some interpret this as spanning an incredibly long lifetime [אבן עזרא].
A promise of constant, sudden joy presents a challenge, as human nature naturally adapts to good circumstances, causing excitement to fade over time. To overcome this, God will change human nature itself, allowing people to experience continuous renewal and unending joy without it ever feeling ordinary [מלבי״ם]. The primary approach among commentators is that this divine act of creation does not mean making something out of nothing. Instead, it refers to a complete renewal and a fundamental shift in the existing world [רד״ק, אבן עזרא]. Another view suggests that the people of Israel and Jerusalem themselves are what God will recreate and renew [שד״ל].
Jerusalem and its people will undergo a total transformation. The primary approach among commentators is that the city will become the very essence of joy, and the people will become a brand-new creation defined by gladness [שד״ל, ביאור שטיינזלץ]. Some even suggest that their actual names will be replaced with words meaning joy and gladness [רד״ק, מצודת דוד]. Jerusalem will serve as the source of constant, internal joy because of the divine light and God's presence resting within it. Meanwhile, the people, through their growth and success, will serve as the outward, visible expression of that happiness [מלבי״ם]. Even though peace and goodness will ultimately spread to the entire world, Jerusalem is given special attention because it is the heart of this new reality, serving as the center from which peace and spiritual teaching will flow to all nations [רד״ק].