7:1 In the first year of Belshazzar king of Babylon Daniel had a dream and visions of his head upon his bed: {a} then he wrote the dream, [and] told the sum of the matters.
(a) Whereas the people of Israel looked for a continual peace, after the seventy years which Jeremiah had declared, he shows that this rest will not be a deliverance from all troubles, but a beginning. And therefore he encourages them to look for a continual affliction until the Messiah is uttered and revealed, by whom they would have a spiritual deliverance, and all the promises would be fulfilled. And they would have a certain experience of this in the destruction of the Babylonian kingdom.
7:1 In the first year of Belshazzar - This prophecy is written in Chaldee, to be a monument to him, of the reverence his father and grandfather shewed towards God, who had done such mighty works for them. Then he wrote - These visions were recorded for the benefit of the church, to rectify their mistake: for they thought all things would succeed prosperously after they returned out of their captivity.
7:1-8 This vision contains the same prophetic representations with Nebuchadnezzar's dream. The great sea agitated by the winds, represented the earth and the dwellers on it troubled by ambitious princes and conquerors. The four beasts signified the same four empires, as the four parts of Nebuchadnezzar's image. Mighty conquerors are but instruments of God's vengeance on a guilty world. The savage beast represents the hateful features of their characters. But the dominion given to each has a limit; their wrath shall be made to praise the Lord, and the remainder of it he will restrain.