Even the most powerful rulers ultimately act as instruments of a higher purpose. The great Babylonian king Nebuchadrezzar, despite his massive conquests, is presented merely as a laborer carrying out the tasks assigned by his Master. His military campaigns are actually missions directed by God, and like any worker, he is entitled to a wage for his efforts [ביאור שטיינזלץ]. The primary approach among commentators is that this payment is owed for the exhausting military labor he invested in the long siege of Tyre, a campaign undertaken at God's command. The nature of this compensation highlights the specific kind of effort he put forth. Rather than a general reward that a leader might receive for having others do the work, the payment recognizes his direct, personal labor, driven by a desire to earn the glory of the deed itself [מלבי״ם].
To compensate him for this intense effort, God hands over the land of Egypt to Babylon. However, Egypt is not merely used as an empty currency to pay off a divine debt. Instead, the nation is handed over as a direct punishment for the evil it committed. Egypt's primary offense, which is considered an act against God Himself, was serving as a false support for the Israelites. By making empty promises and planting false hopes of military aid, the Egyptians actively caused Israel to stumble. Therefore, the fall of Egypt serves a dual purpose: it provides the Babylonians with their rightful wage for their hard work, while simultaneously punishing Egypt for its pride and its historic sins against Israel [אברבנאל].