'O God' in the Bible

Then thou shalt go forth from thence and shalt come to the oak of Tabor. And there shalt thou meet three men going to God to Bethel: one carrying three kids; and another carrying three loaves of bread; and the third carrying a bottle of wine.

And so God helped Israel that day. And the battle continued until they came unto Bethaven.

And Saul said, "Let us go down after the Philistines by night, and let us make havoc among them until it be day in the morning, and let us not leave one of them." And the people answered, "Do whatsoever thou thinkest best." Then said the priest, "Let us come hither unto God."