בראשית, פרק א׳, פסוק ט״ו

The positioning of the celestial bodies is not merely a physical phenomenon, but a deliberate design intended to sustain life below. While their initial role was to regulate times, seasons, and the division between day and night, they were given an equally vital function: to cast actual, physical light across the earthly realm. The primary approach among commentators is that this introduces a distinctly new purpose [רש״י, גור אריה, מזרחי, שפתי חכמים]. Because they are inherent sources of light, they are practically utilized as such [קאסוטו].

Theoretically, the sun, moon, and stars could have remained in the heavens, fulfilling their astronomical duties of setting the calendar without their light ever reaching the ground. Thus, it is emphasized that their illumination is intentionally directed downward [רמב״ן, שד״ל, ביאור יש״ר]. Unlike a standard candle that scatters its glow indiscriminately in all directions, the radiance of the heavens is focused, gazing deliberately toward the Earth [העמק דבר]. Suspending these massive bodies at such a high altitude is simply the most natural and efficient method to illuminate the entire expanse [חזקוני].

Since the physical earth has no inherent need for light, this illumination is clearly designed for its inhabitants [מזרחי, שפתי חכמים]. It provides more than just the absence of darkness; it is an active, beneficial force for the masses [יריעות שלמה]. While the establishment of seasons and signs caters specifically to humanity, the light itself nurtures every facet of existence—inanimate matter, plants, animals, and humans alike [אדרת אליהו]. Even though mankind had not yet been formed, this light was required immediately to grow and ripen the vegetation that had emerged earlier in the week [חזקוני]. It exerts a powerful physical influence on everything in the lower world, affecting each creation exactly as it requires [רד״ק].

This entire system of illumination was engineered with exact precision. The light reaching the ground is not overwhelmingly intense, but moderated, pleasant, and perfectly suited for those living below [ספורנו]. If these glowing bodies were positioned any closer, the world could not withstand their immense power. God intentionally placed them high in the firmament so that their energy diffuses and filters through the atmosphere, reaching the surface only in a measure that life can endure [אור החיים]. On a broader cosmic scale, while these celestial bodies reflect light upon one another—such as the sun casting its rays onto the moon and stars—the ultimate purpose of this vast astronomical network is to illuminate the Earth [מלבי״ם].

Once this intricate system was established, the design was brought to completion. Some explain that at that exact moment, the celestial bodies stood ready, waiting before God until they were physically suspended in the sky [העמק דבר], or that the precise, necessary moderation of their light was permanently set [ספורנו]. Others view this finalization as a testament to the eternal nature of creation. Just as God commanded the system to operate in that moment, so it remains forever. The orbital paths, the cosmic roles, and the laws of nature were permanently engraved, never deviating even a fraction from their ancient course [מלבי״ם, קאסוטו].