Absolute control over the dimensions of time, nature, and the universe rests entirely in the hands of God. The cycles and contrasts found throughout creation are not random occurrences, but rather clear evidence of a single Creator who guides everything for the ultimate benefit of His world.
The primary approach among commentators is that God's ownership of both the light and the darkness expresses His absolute mastery over all time. Because God alone established the laws of nature and the daily orbits of the celestial bodies, He possesses the power to alter or overturn nature at will in order to save His servants [רד״ק, מלבי״ם]. God designed every phase of time with a specific purpose. While the darkness might appear to be nothing more than the absence of light [מלבי״ם], it was intentionally created to provide a necessary period of rest for humanity and an opportunity for animals to seek their food [רד״ק].
To maintain this cycle, God set the heavenly bodies on a firm and permanent foundation, ensuring they remain stable and faithfully carry out their designated roles [ביאור שטיינזלץ, מצודת ציון, מצודת דוד]. Within this system, the moon is intimately linked to the darkness it governs [אבן עזרא, מצודת דוד], even as it derives its illumination directly from the sun [מלבי״ם].
This flawless cosmic order serves as a profound philosophical proof for the belief in a single, unified Creator. The reality that the sun and the moon each appear at their precise time and location proves that both are governed by a single authority. If there were separate ruling powers for the light and the darkness, such perfect harmony could never exist. It was precisely through observing this exact, harmonious order that Abraham first came to recognize the Creator of the world [אלשיך].
Beyond the physical reality of the solar system, there is a deep spiritual and symbolic layer to these natural cycles. The bright hours of the day symbolize God's trait of mercy and represent periods of redemption for the people of Israel [אלשיך]. Conversely, the darkness represents the trait of strict justice, reflecting times of hardship and exile [אלשיך]. Through this allegorical lens, the heavenly bodies are not merely physical stars and planets. Instead, they represent the spiritual light of the Torah, which God carefully prepared and gifted to His people to guide them through both the bright and dark periods of their history [רש״י].