תהלים, פרק פ״ט, פסוק ל״ח

God seals His promise for the eternal survival of the Davidic dynasty by comparing it to the most stable forces in the natural world. The primary approach among commentators is that looking to the sky provides a picture of permanence; just as the sun and the moon endure forever, the descendants of David are guaranteed to sit upon the royal throne for all time [אבן עזרא, מצודת דוד, ביאור שטיינזלץ].

Beyond simply existing forever, the imagery of the moon carries a deeper meaning regarding its natural cycles. The moon transitions through phases of bright illumination and deep darkness, yet it never truly vanishes. In the same way, the royal line of David will experience eras defined by the light of good deeds, as well as eras darkened by sin. Through all these changing times, however, the kingship itself will never be entirely extinguished [רד״ק].

A promise of such magnitude is accompanied by a faithful witness in the heavens. The primary approach among commentators is that this refers to the celestial bodies themselves—the sun, the moon, or the stars. Fixed permanently in the sky, they serve as stable, eternal witnesses to this covenant. As long as these heavenly bodies remain, the royal dynasty will continue, reinforcing the strength of the divine guarantee [רש״י, רד״ק, אבן עזרא, מצודת דוד, ביאור שטיינזלץ]. Alternatively, another perspective suggests that the faithful witness in the heavens is God Himself. While human witnesses on earth are mortal and eventually pass away—requiring at least two people to securely establish a matter—God is a single, heavenly, and eternal witness who personally guarantees the survival of the dynasty [אלשיך].