'O God' in the Bible

Neither for his father nor for his mother nor for his brother nor for his sister, shall he make himself unclean-not even for them, should they die, - because, his separation unto God, is upon his head,

Then Moses made outcry unto Yahweh, saying, - O GOD, I beseech thee grant healing. I beseech thee unto her.

And they fell upon their faces and said, O GOD, the God of the spirits of all flesh, - shall, one man, sin, and against all the assembly, wilt thou he wroth.

Then said Balaam unto God, - Balak, son of Zipper king of Moab, hath sent unto me: