With the coming of the Persian king Cyrus, Babylon, the great nation, the “queen of kingdoms” (chapter 47) would fall.
God had used Babylon to punish His people. You’d think He’d be grateful for their help and ensure their future.
But no. Babylon, while the tool of God’s discipline, went further than they had a right to go, showing no mercy to the people of the Lord. More than that, though their success was totally assured by the God of Israel, the Babylonians refused to acknowledge Him. Instead, they had pursued religions of astrology, magic and sorcery.
How was Babylon supposed to acknowledge the Lord as supreme when they didn’t know about Him? As we see in chapter 49, it was Israel’s job to make the Lord known; but whether they did nor not, ignorance was no excuse. Chapter 47 speaks to the sovereignty of God. He uses nations as He sees fit, then holds them accountable for the way they act. He can do it. He is God.