'O God' in the Bible

And he said to him, Thus saith the LORD, Forasmuch as thou hast sent messengers to inquire of Baal-zebub the god of Ekron, is it not because there is no God in Israel to inquire of his word? therefore thou shalt not come down off that bed on which thou art gone up, but shalt surely die.

And he returned to the man of God, he and all his company, and came and stood before him: and he said, Behold, now I know that there is no God in all the earth, but in Israel: now therefore, I pray thee, take a blessing from thy servant.

And have cast their gods into the fire: for they were no gods, but the work of men's hands, wood and stone: therefore they have destroyed them.