Charles Ellicott Commentary Daniel 2:18

"that they would desire mercies of the God of heaven concerning this secret; that Daniel and his companions should nor perish with the rest of the wise men of Babylon." — Daniel 2:18 (ASV)

The God of heaven.— We encounter this title of Almighty God for the first time in Genesis 24:7. After the Captivity, it frequently designates the true God as contrasted with the heathen gods. (See Ezra 1:2, Nehemiah 1:5, Psalms 136:26.) It is used by Daniel in this sense in this verse.