These verses show God's supremacy over the nations. Twice God states through Daniel that He, the supreme Creator and Ruler, gave Nebuchadnezzar his dominion over men.
John W. Ritenbaugh
The Sixth Commandment (Part 2): War! (1997)
Daniel 2:36-43 describes four major kingdoms, empires, or governmental systems that have ruled over the greater part of the civilized world:
1. The Chaldean-Babylonian Empire (625 to 538 BC)
2. The Medo-Persian Empire (538 to 330 BC)
3. The Greco-Macedonian Empire (333 to 31 BC)
4. The Roman Empire (Established 31 BC. The imagery suggests that it will exist in some form until the end of the age.)
Clearly, these physical empires existed on earth. Verses 44-45 then say that God's Kingdom will encompass all of these previous kingdoms—on earth! Daniel 7:17-18 says much the same.
Is Heaven the Reward of the Saved?