'O God' in the Bible

And they were helped against them, and the Hagarites were delivered into their hand, and all who were with them. For they cried to God in the battle, and He was pleased to hear them, because they put their trust in Him.

And say, Save us, O God of our salvation, and gather us, and deliver us from the nations, so that we may give thanks to Your holy name, and glory in Your praise.

And this was a small thing in Your eyes, O God, for You have also spoken of Your servant's house for a great while to come, and have regarded me according to the estate of a man of high degree, O Jehovah God.

And David said to God, I have sinned greatly because I have done this thing. But now, I beseech You, remove the iniquity of Your servant for I have done very foolishly.

And David said to God, Did not I command to number the people? I am the one who has sinned and done evil indeed. But these sheep, what have they done? I pray You, let Your hand be on me, O Jehovah my God, and on my father's house, but not on Your people, that they should be plagued.