God's absolute sovereignty over the entire universe serves as the ultimate proof of His power to redeem His people at any moment. By demonstrating complete control over both the heavens and the earth, He shows that neither the laws of nature nor the course of history can stand in the way of salvation, as He possesses the power to bring total darkness and mourning to the world [שד״ל, ביאור שטיינזלץ].
The deep blackness brought upon the world is understood in a physical sense as a profound, literal darkness [מצודת ציון]. Commentators offer different perspectives on how this manifests. Some explain it as thick clouds, heavy rain, and dense fog rolling in to obscure the sky, while others view it as a sudden solar eclipse turning midday into night [אבן עזרא, רד״ק, מלבי״ם]. The darkened sky is compared to sackcloth because the coarse material is naturally black in its fibers [אבן עזרא, רד״ק]. A subtle distinction exists in how this darkness is draped over the world. One form of covering evokes a fitted garment, much like clouds that spread perfectly across the expanse of the sky. Another describes a loose, formless layer, similar to a thick fog or mist that fills the air without taking on a specific shape [מלבי״ם].
Historically, this dramatic darkening of the skies serves as a powerful reminder of the Plague of Darkness in Egypt. God declares that just as He altered the very foundations of nature to free the Israelites from Egyptian slavery, He retains the exact same power to perform wonders today. He can redeem the Israelites from their current exile, even as they are scattered across many different nations [רד״ק, צאינה וראינה].
On a deeper conceptual level, the heavens represent more than just the physical sky overhead. They symbolize the spiritual powers guiding the other nations, the heavenly hosts, and the astrological signs, as well as the wealth and success those nations enjoy. When God steps in to punish these nations for the harm they have caused Israel, He cuts off their prosperity, wrapping them instead in darkness and ruin [רש״י, רד״ק]. This serves as a direct response to those who claim that the exile of the Israelites is dictated by the stars or an unchangeable astrological order. God demonstrates that He can simply cover and cancel out the power of the zodiac. The ultimate downfall of the wicked does not rely on the laws of nature or heavenly bodies, but solely on His direct and purposeful providence [אהבת יהונתן, מלבי״ם].