has your God … been able: There was no doubt that Daniel had served God faithfully. So, if God did not rescue him, it would have shown the king that God could not do so.
living God: The king likely knew what Daniel’s God had done during the reigns of Nebuchadnezzar and Belshazzar. The term living God is used in the Bible to compare the Lord with lifeless idols (see, for example, Deuteronomy 5:26; Joshua 3:10; Isaiah 37:17–18).