'O God' in the Bible

And Solomon said unto God, Thou hast showed great lovingkindness unto David my father, and hast made me king in his stead.

and he said, O Jehovah, the God of Israel, there is no God like thee, in heaven, or on earth; who keepest covenant and lovingkindness with thy servants, that walk before thee with all their heart;

Have ye not driven out the priests of Jehovah, the sons of Aaron, and the Levites, and made you priests after the manner of the peoples of other lands? so that whosoever cometh to consecrate himself with a young bullock and seven rams, the same may be a priest of them that are no gods.

Now therefore let not Hezekiah deceive you, nor persuade you after this manner, neither believe ye him; for no god of any nation or kingdom was able to deliver his people out of my hand, and out of the hand of my fathers: how much less shall your God deliver you out of my hand?