What does Daniel 4:26 mean?
Following a dire prediction of insanity and humiliation (Daniel 4:24–25), King Nebuchadnezzar receives some good news. In his dream, the king was symbolized as a tree cut down to a stump (Daniel 4:10–14). Yet the stump's roots were left intact, so that it could one day begin to sprout new growth (Daniel 4:15).As Daniel now explains, the tree's surviving stump and roots indicate that Nebuchadnezzar's isolation and animal-like existence will end. He will not only survive this madness, but he will rule his kingdom once again. This return to sanity will only happen once the king comes to appreciate that he is merely a man: he is not divine. True power is not found in Babylon, but in Heaven. The supreme Lord is not Nebuchadnezzar, but the Lord God. The context of Daniel's comment suggests that "heaven" is being used as a euphemism for God, which is why many translations capitalize the term as "Heaven(s)."
In His grace and mercy God would limit the two punishments. Nebuchadnezzar's insanity would last only a limited time. Some Bible teachers suggest that Daniel took Nebuchadnezzar's place as king, but this is purely speculation. There is no biblical or secular mention of Daniel ruling Babylon. Indeed, it is an unlikely occurrence. If Daniel had occupied such a powerful position, he probably would have restored the captive Hebrews to their homeland. In fact, there is no other record of Nebuchadnezzar suffering in this way. A possible reason is that a temporary government was established—likely in secret—until the madness had passed.