'O God' in the Bible

And it came to pass in process of time, that the king of Egypt died: and the children of Israel sighed by reason of the bondage, and they cried; and their cry ascended to God, by reason of the bondage.

And Moses said to God, Who am I, that I should go to Pharaoh, and that I should bring forth the children of Israel out of Egypt?

And Moses said to God, Behold, when I come to the children of Israel, and shall say to them, The God of your fathers hath sent me to you; and they shall say to me, What is his name? What shall I say to them?

Hearken now to my voice, I will give thee counsel, and God shall be with thee: Be thou for the people toward God, that thou mayest bring the causes to God:

And Moses went up to God, and the LORD called to him from the mountain, saying, Thus shalt thou say to the house of Jacob, and tell the children of Israel;