Do you suppose that the Jews respected Nebuchadnezzar, when he besieged their home nation of Judah, when he took them captive and when he carried them back to Babylon as his prisoners of war? Yet, it is under his rule as tyrant king that the Lord revealed to him and to His people “that the Most High rules in the kingdom of men, and gives it to whomever He chooses” (Dan. 4:17, 25, 32). 
The primary lesson was for that arrogant man to know his place in the affairs of the Most High God. But, there is also a lesson for every man, including us today.
God wanted Nebuchadnezzar to “know…know…know…know” (4:17, 25, 26, 32) that “Heaven rules” (4:26). No matter who is on the throne or in leadership, we must always remember who is on the Most High throne! And He is the one who placed those on “earthly thrones” in those positions of leadership. Thus, the Most High God deserves our submission and our respect. But, so does the earthly leader, no matter who he/she is (Rom. 13:1-7; 1 Pet. 2:13-17).