'O Lord My God' in the Bible

And now, O LORD my God, thou hast made thy servant king instead of David my father: and I am but a little child: I know not how to go out or come in.

Yet have thou respect to the prayer of thy servant, and to his supplication, O LORD my God, to hearken to the cry and to the prayer, which thy servant prayeth before thee this day:

And he cried to the LORD, and said, O LORD my God, hast thou also brought evil upon the widow with whom I sojourn, by slaying her son?

And he stretched himself upon the child three times, and cried to the LORD, and said, O LORD my God, I pray thee, let this child's soul come into him again.