God's absolute and infinite greatness means that any human attempt to contain His glory or appease Him with material wealth is bound to fail. Even the most vast and magnificent natural resources are entirely dwarfed by His honor and justice. To illustrate this, prophetic imagery draws upon the famous, massive forest of Lebanon [מצודת ציון, רד״ק], which stands as a symbol for all the trees in the world [אבן עזרא].
Despite its sheer size, this immense forest does not hold enough wood to fuel the fire on God's altar [רש״י, מצודת ציון, ביאור שטיינזלץ]. Similarly, the countless wild animals roaming within it [ביאור שטיינזלץ] are simply not enough to be offered as burnt offerings before Him [מצודת דוד]. This presents a surprising rhetorical turn. After earlier descriptions reduced the powerful forces of nature and mighty nations to mere specks of dust, one might expect the majestic mountains of Lebanon to be dismissed as equally insignificant. Instead, the perspective shifts. It becomes clear that even if the entire forest and its wildlife were dedicated to the noble purpose of sacrifice, it would still fall completely short of giving God the honor He deserves [שד״ל]. Furthermore, God has no actual need for physical sacrifices in the first place [אבן עזרא].
The primary approach among commentators views this message as directed toward the nations of the world, who previously mocked God and doubted His power to redeem Israel. Once these nations witness God saving His people, they will experience deep regret and attempt to appease Him to make up for their actions. However, even if they were to offer an unimaginable bribe consisting of all the trees and animals of Lebanon, it would never be enough to atone for their sins or alter God's promise to redeem Israel [רש״י, רד״ק, מלבי״ם, צאינה וראינה].
A different perspective focuses on the universal balance of justice. According to this view, human sin demands a response from the attribute of strict justice, and animal sacrifices are intended to absorb this punishment in place of the sinner. Yet, human failings are so numerous that all the wildlife in Lebanon could not possibly provide enough atonement. Because the animal kingdom is unable to fully satisfy the demands of strict justice threatening Israel, the nations of the world were created for this specific purpose, ultimately absorbing the strict justice in their place [אהבת יהונתן].