'O God' in the Bible

But we made our prayer to God, and had men on watch against them day and night because of them.

Also I shook my lap, and said, So God shake out every man from his house, and from his labour, that performeth not this promise, even thus be he shaken out, and emptied. And all the congregation said, Amen, and praised the LORD. And the people did according to this promise.

For they all made us afraid, saying, Their hands shall be weakened from the work, that it be not done. Now therefore, O God, strengthen my hands.

For in the days of David and Asaph of old there were chief of the singers, and songs of praise and thanksgiving unto God.

Was it not, over these things, that Solomon king of Israel sinned - though, among many nations, there was no king such as he, and he was, beloved by his God, and so God gave him to be king over all Israel, - even him, did foreign women, cause to sin.