The King of Babylon, standing at the absolute peak of his pride and power, faces a dramatic downfall designed to teach a profound lesson in faith and Divine providence. The primary approach among commentators is that this punishment is entirely personal, crafted specifically to shatter his arrogance. The decree applies only to him, leaving his empire intact to continue without his presence [מלבי״ם, אלשיך].
This downfall operates as a direct measure for measure. Because of his immense pride, instead of being elevated above humanity, the king is cast down below it [יוסף אבן יחיא]. Driven completely away from human society, he is forced to live among the wild beasts, the very creatures that are naturally meant to be under human control [יוסף אבן יחיא]. Stripped of his humanity, he is fed grass like an ox [מצודת ציון] and left completely exposed to the elements. Drenched by the dew of heaven [רש״י, ביאור שטיינזלץ], he suffers through the scorching heat of the day and the biting cold of the night [יוסף אבן יחיא].
He is condemned to remain in this feral state for seven periods or years, a duration that carries distinct meanings. It is viewed as a seven-year punishment directly corresponding to the seven years it took to build the Temple, which the king had previously destroyed [רש״י]. Alternatively, each period represents the influence of one of the seven planets, and only after all seven cycles are complete will his human intellect be restored [מלבי״ם].
The ultimate goal of this exile is to force the king to recognize that the Supreme God rules over all human kingdoms and grants power to whomever He desires. The king mistakenly believed that God had abandoned the earth, leaving it to the control of the stars and heavenly forces. Operating under this false assumption, he attempted to secure an eternal reign by erecting a golden idol and oppressing the Israelites. Because he used his intellect to rebel against God, that very intellect is taken from him and replaced with the heart of a beast [אלשיך].
Daniel subtly alters the message of the original dream to drive this point home. While the dream stated that this would happen so the living will know, Daniel tells the king it will happen until he personally knows. This shift deliberately humbles the king, highlighting that he alone lacks this fundamental understanding. Yet, within this strict judgment lies a profound measure of mercy. God preserves both the king's life and his throne completely unharmed. This ensures that once his sanity is restored and he reclaims his crown, the king himself will publicly declare God's power and absolute rule to all the nations of the world [אלשיך].