King Darius did not know whether Daniel's God was able to deliver him or not, but that was never a question with Daniel. This is the difference between those who have been given divine knowledge and understanding and those who have not. To Darius there were "gods many, and lords many," but to Daniel there was "but one God" (See I Cor. 8:5-6) and that was "the Father, of whom are all things, and we by him," etc. Darius was familiar with gods who were not able to deliver those who served them, and he thought Daniel's God might be one of them. But Daniel was acquainted with the one true and living God, and knew that He could not fail nor be discouraged (See Isaiah 42:4).
    We frequently hear people among the popular religions of the day talking about what their god wants to do, and what he will do if we will let him. They speak of what he is trying to do and of the frustration he feels because of the millions who are supposedly being lost that he would like to have saved but could not because they would not allow him to do so. Such a god is not the God of Daniel and neither is he the god of any other true believer. The God of true believers is that Majestic Being described by Nebuchadnezzar in Daniel 4:35, who does according to His will in the army of heaven, and among the inhabitants of earth: and none can stay His hand, or say unto Him, What doest Thou? He is the same whose works are truth, and His ways judgment, and who is able to abase those who walk in pride (See Dan. 4:35-37).
    What would be your answer, dear reader, if you were asked if your God was able to deliver you from the lions? My own reply would be a resounding, Yes! Not only is He able, but figuratively speaking I believe He has many times done so. There have been those who would have "swallowed me up quickly" if the Lord had "given me up as a prey to their teeth" (See Psalm 124:3,6). How thankful we should be that He is not only able to deliver us but often does deliver us, no doubt many times when we are not even aware of it.