God holds absolute control over human history, often guiding the hearts of world leaders to achieve His divine plans. A mighty foreign emperor can serve as an instrument of redemption, setting in motion a political miracle driven entirely by the will of Heaven rather than ordinary earthly interests.
The primary approach among commentators is that this prophecy centers entirely on Cyrus, the King of Persia. It is God Himself who stirs the king's heart to take action [מצודת ציון, אבן עזרא]. This divine awakening is rooted in a profound sense of justice, which unfolds in two complementary ways. On one hand, it brings justice to the Israelites by freeing them from exile and rescuing them from their oppressors [מלבי״ם, רד״ק, ביאור שטיינזלץ]. On the other hand, it executes a well-deserved punishment against the Babylonian empire, bringing about its destruction for its past cruelties [מצודת דוד, רד״ק].
To guarantee the emperor's success, God promises to smooth his path so that he will not stumble or fail [מצודת דוד]. God prepares all the necessary means and resources for him [מלבי״ם] to achieve one clear objective: the rebuilding of Jerusalem [אבן עזרא]. Cyrus is not merely expected to grant permission for this construction; he is to personally provide the gold and funds required to rebuild the city and the Temple [מצודת דוד, רד״ק]. At the same time, he will completely release the exiled Israelites, allowing them to return to their homeland [מצודת דוד].
The most extraordinary aspect of this historical event is the complete absence of any financial or political expectation. In the normal course of the world, a builder demands payment for construction, and a powerful ruler requires a ransom or bribe to free captives. Yet, Cyrus undertakes this massive effort without asking for anything in return [מלבי״ם]. Furthermore, political gestures of this scale usually extract a heavy political cost, but the Jewish people at that time lacked the standing or influence to offer the Persian king any strategic advantage [ביאור שטיינזלץ].
Ultimately, the emperor's true motivation is neither economic nor political. He acts of his own free will [ביאור שטיינזלץ], driven by a deep, internal recognition that it is God who crowned him and granted him his vast power. Recognizing this divine gift, Cyrus simply desires to fulfill the will of his Creator [רד״ק, מלבי״ם].