'O God' in the Bible

So Moses cried out to the Lord, saying, “Heal her please, O God, I plead with You!”

But they fell on their faces [before the Lord], and said, “O God, God of the spirits of all flesh! When one man sins, will You be angry with the entire congregation?”

But the firstborn of a cow or of a sheep or of a goat you shall not redeem; they are holy [and belong to the Lord]. You shall sprinkle their blood on the altar and shall offer up their fat in smoke as an offering by fire, for a sweet and soothing aroma to the Lord.

Balaam said to God, “Balak the son of Zippor, king of Moab, has sent word to me: