"'O king, the Most High God gave your father Nebuchadnezzar sovereignty and greatness and glory and splendor. Because of the high position he gave him, all the peoples and nations and men of every language dreaded and feared him. Those the king wanted to put to death, he put to death; those he wanted to spare, he spared; those he wanted to promote, he promoted; and those he wanted to humble, he humbled. But when his heart became arrogant and hardened with pride, he was deposed from his royal throne and stripped of his glory. He was driven away from people and given the mind of an animal; he lived with the wild donkeys and ate grass like cattle; and his body was drenched with the dew of heaven, until he acknowledged that the Most High God is sovereign over the kingdoms of men and sets over them anyone he wishes.'" NIV translation
Before he interprets the writing, Daniel gives the young king a little history lesson. His grandfather had been elevated to the position of the greatest kingdom in the world. He had power and authority that were unmatched by any man but pride became his downfall. The prophet recounts how his grandfather was humbled to the point of insanity and acting like a wild animal. He was also reminded that the reason for this was his elevating himself to a position equal to God. Belshazzar must have started feeling a little unease as he wondered why Daniel was giving him this little history lesson.
This should be a reminder to us of the importance of sharing with our children and grandchildren what God has done and is doing in our lives. The first witnessing of a Christian begins at home; when it does not, you end up with the same type of situation that we see with Belshazzar.
"'But you his son, O Belshazzar, have not humbled yourself, though you knew all this. Instead, you have set yourself up against the Lord of heaven. You had the goblets from his temple brought to you, and you and your nobles, your wives and your concubines drank wine from them. You praised the gods of silver and gold, of bronze, iron, wood and stone, which cannot see or hear or understand. But you did not honor the God who holds in his hand your life and all your ways. Therefore he sent the hand that wrote the inscription.'" NIV translation
Belshazzar had known about what had happened with his grandfather but did not take it to heart. Instead, he went about partying it up and even went so far as to defile the things of God. He worshiped the material things (false gods) and ignored the fact that God was in charge of his life. Daniel tells him that this is the reason that God sent the hand to proclaim his fate. This same type of thing is happening more and more today as many people chase material things and forget the more important matters of life itself.
"'This is the inscription that was written: MENE, MENE, TEKEL, PARSIN This is what these words mean: Mene: God has numbered the days of your reign and brought it to an end. Tekel: You have been weighed on the scales and found wanting. Peres: Your kingdom is divided and given to the Medes and Persians.'" NIV translation
God simply was telling Belshazzar that his number was up and his kingdom was going to be split in two because of the fact that he did not acknowledge that God was in charge. This is the same thing that God had showed Belshazzar's grandfather as we saw in chapter 2 with the statue.